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https://www.duolingo.com/profile/daKanga

[GUIDE] Time zones

UTC - a common time language - is important for a world wide community

We are a global community, and being able to talk about time and "be on the same clock" is beneficial to us. This is why this post is relevant to our language learning community.

There is a world wide standard used to express time, and is used by so many enterprises - known as Coordinated Universal Time (UTC). Though a roo like me likes to think of it as Universal Time Coordination, as it confuses me less. ( For more info: see here )

To cut to the chase, lets say you are in Pittsburgh, United States of America.

The easiest way to find out what your UTC offset is :
Google : "what is my time zone"
https://www.google.com/search?q=what%2Bis%2Bmy%2Btime%2Bzone
i.e. click on this blue writing above. If in Google you hold down your "ctrl" key, and then click, it will open this in a new tab for you, keeping this page in this tab. ( As recommended by dogomolo )

Back to our Pittsburgh's example, whose UTC offset is:

  • UTC-04 during the middle of the year - in their summer Duo31, and
  • UTC-05 for the winter, at the end and beginning of their year.
    Pittsburgh time

It is sooo much more useful knowing your relevant UTC offset time zone number, than knowing your time zone is a code like EST/EDT.

To convert UTC time to your local time :

If someone from around the world asks can we have a chat at UTC 12:00, and currently you are in "summer time" in Pittsburgh Duo31, you take 12 (the UTC time for catching up) and subtract 4 (your UTC offset zone) = 8:00am ( 12 - 4 = 8 ) .

(UTC time) + (your UTC offset) = (your local time)
Note: if your UTC offset is negative (as is the case for Pittsburgh), you SUBTRACT the offset from the UTC time. ie 12 + (-4) = 12 - 4 = 8

You do no need to know which time zone they are in, nor if it is summer or winter there. They do not need to know if where you are has a different time zone in summer time to winter time. The only key you need is to know what your relative "offset" to UTC time is. For the other person, the only key they need to know is what their relative "offset" is to UTC time. i.e.

  1. To Google their UTC offset
  2. Take the UTC time that that has been given to catch up, and to follow across the table to where your relative UTC offset column is.

List of tables for all UTC offset zones


To convert your local time to UTC time :

If you are in Pittsburgh and you want to give someone a time you wish to connect with them, and it is summer time, you add 4 hours to the time you want to catch up. So, say you want to catch up at 14:00 (2 pm) Pittsburgh summer time, you add 4 to 14, makes 18. (14 + 4 = 18) So you agree on 18:00 UTC. That way they do not have to try to work out if you are on summer or winter time. They just need to do the calculation for their time zone. And you don't have to worry if they are on summer or winter time. You leave that to them.

(your local time) - (your UTC offset) = (UTC time)
note: if your UTC offset is negative, (as is the case for Pittsburgh) , you ADD the UTC offset to your local time. ie 14 - (-4) = 14 + 4 = 18


If you are in Pittsburgh, and you want to convert you time schedule into and out of UTC time, this is the only table you need. Or for some of us, they do the calculation in their head. This table though could prove to be a good proof of principal/cross check.

Pittsburgh time to UTC time ( winter and summer time )

-5 -4 Duo31 UTC
19:00 *¹ 20:00 *¹ 00:00
20:00 *¹ 21:00 *¹ 01:00
21:00 *¹ 22:00 *¹ 02:00
22:00 *¹ 23:00 *¹ 03:00
23:00 *¹ 00:00 04:00
00:00 01:00 05:00
01:00 02:00 06:00
02:00 03:00 07:00
03:00 04:00 08:00
04:00 05:00 09:00
05:00 06:00 10:00
06:00 07:00 11:00
07:00 08:00 12:00
08:00 09:00 13:00
09:00 10:00 14:00
10:00 11:00 15:00
11:00 12:00 16:00
12:00 13:00 17:00
13:00 14:00 18:00
14:00 15:00 19:00
15:00 16:00 20:00
16:00 17:00 21:00
17:00 18:00 22:00
18:00 19:00 23:00

*¹ One calendar day BEHIND the UTC calendar date.

ref: https://docs.google.com/spreadsheets/d/1TxEAPixfUxVBAgmAmlYugQHrhh4fcOim_V_ydrC8O-c/edit?usp=sharing


Getting the right calendar DATE

Hopefully now you can work out how to express whatever time zone you are in to get UTC time.

YET, there is one other skill you need. How to also convert into and out of the correct calendar date. ( It is not a good scene to miss an event by 24 hours ;P ) If you are in a minus time zone, such as Pittsburgh, there are times in your day that you are behind in your calendar date to UTC time.
For those in UTC-5 zone, this will be one day behind for your times of 19:00 to midnight. From 19:00 to midnight if you are in the UTC-5 zone, UTC time will be one calendar date ahead of you.
For those in UTC-4 zones, this will be one day behind for your times of 20:00 to midnight. From 20:00 to midnight if you are in the UTC-4 zone, UTC time will be one calendar date ahead of you.

Now that was not too hard ? If it was, do read another explanation here, and/or ask questions. Or have a go at explaining it in your words. This may also help others.

Future time changes for Northern American Time zones

EDT/EST ; CDT/CST ; MDT/MST ; PDT/PST
Daylight Saving Time (DST)

year date offset
2019 10 Mar +1 (DST start) Duo31
3 Nov -1 (DST end)
2020 8 Mar +1 (DST start) Duo31
1 Nov -1 (DST end)
2021 14 Mar +1 (DST start) Duo31
7 Nov -1 (DST end)
2022 13 Mar +1 (DST start) Duo31
6 Nov -1 (DST end)

ref: https://www.timeanddate.com/time/zone/usa/pittsburgh


Indicative reference: it is important to check the town/city/region for an accurate UTC

Northern Hemisphere

Description End-Start year Mid Year Duo31
USA-PDT/PST -8 -7
USA-MDT/MST -7 -6
USA-CDT/CST -6 -5
USA-EDT/EST -5 -4
Central Europe +1 +2
China +8 +8

Southern Hemisphere

Description End-Start YearDuo31 Mid Year
Australia-East +11 +10

Please also feel free to contribute your way of explaining how to use UTC. Your explanation could easily be clearer than mine, and make more sense to other sections of our community, and thus assist all of us to communicate.

ps. Knowing this is also really beneficial when you travel to different time zones ;P

last updated 2019/07/28 00:00 UTC [GUIDE] Time zones

July 19, 2019

50 Comments


https://www.duolingo.com/profile/FranM2

Its abbreviation actually has to do with languages.

English speakers proposed CUT (coordinated universal time) while the French wanted TUC (temps universel coordonné) so they chose the middle ground UTC (universal time coordinated/universel temps coordonné).

July 19, 2019

https://www.duolingo.com/profile/daKanga
Mod
  • 302

WOW thank you for this knowledge !

July 19, 2019

https://www.duolingo.com/profile/daKanga
Mod
  • 302

I know this is not about language, this post.
However there are things at times that as a global community we coordinate between us. And for us to all be up to speed on this issue could greatly assist us as a community that is spread across the world.

July 19, 2019

https://www.duolingo.com/profile/Songve

Half our life is spent trying to find something to do with the time we have rushed through life trying to save. ~ Will Rogers

July 19, 2019

https://www.duolingo.com/profile/SecretlyAHippo

Woah. That's a great quote.

July 19, 2019

https://www.duolingo.com/profile/Songve

I look out my window. The sun is shining. It is daytime. In military we used Zulu Time formerly Greenwich Mean Time, as the UTC. That reminds me. I need to set the clock I have in my gazebo. It is...time out.

July 19, 2019

https://www.duolingo.com/profile/daKanga
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  • 302

CEST – Central European Summer Time (Daylight Saving Time) is at UTC+2 : https://www.timeanddate.com/time/zones/cest3
It is used during summer for : Europe, Antarctica.
And in winter, the time zone is CET at UTC+1
ie. Paris

https://www.timeanddate.com/time/zone/france/paris

This is the time zone I am currently in, and it is UTC+2

Here is the table for calculating UTC to/from UTC+1 (winter), and UTC+2 (summer) for Central Europe

UTC +1 +2 Duo31
00:00 01:00 02:00
01:00 02:00 03:00
02:00 03:00 04:00
03:00 04:00 05:00
04:00 05:00 06:00
05:00 06:00 07:00
06:00 07:00 08:00
07:00 08:00 09:00
08:00 09:00 10:00
09:00 10:00 11:00
10:00 11:00 12:00
11:00 12:00 13:00
12:00 13:00 14:00
13:00 14:00 15:00
14:00 15:00 16:00
15:00 16:00 17:00
16:00 17:00 18:00
17:00 18:00 19:00
18:00 19:00 20:00
19:00 20:00 21:00
20:00 21:00 22:00
21:00 22:00 23:00
22:00 23:00 00:00 *²
23:00 00:00 *² 01:00 *²

*² One calendar day AHEAD the UTC calendar date.

So if someone asks me to catch up at UTC 16:00, I can look at this table and see this would be at 18:00 my time, while I'm in France during Summer time/midyear.

July 19, 2019

https://www.duolingo.com/profile/dogomolo

One should be able to export your tables. Otherwise they are not very easy to reference later. In addition Microsoft Excel can be used to generate any such table (I haven't tested):

https://support.office.com/en-us/article/add-or-subtract-time-16aa6697-6d6e-49c1-8e2c-3398a7cad6ad

July 19, 2019

https://www.duolingo.com/profile/daKanga
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  • 302

ohhhhh - Duo18
I love reading about things such as this, thank you.

However a lot of my friends also have lots of trouble with spreadsheets, so I also try to provide them the information in different ways, so that they are able to use it.

Again, thank you for this information.

July 19, 2019

https://www.duolingo.com/profile/n35w101

Timezones are, ultimately, a parochial method of making people think their corner of the world is special because the sun is overhead at noon.

As humanity moves out into space and settles on other worlds, nobody on those worlds will want to bother with keeping track of "local" time for any given Earth city.

The planet will ultimately have a single, global time. And people will adjust their way of identifying their local time & schedules.

For example, let's assume Earth Global Time (EGT) = current UTC.

Currently ... I live in UTC -5. The sun rises around 6:30AM. My workday starts at 7:30AM and ends at 4:00PM. But all those time values are predicated on my "timezone".

In the future ... I live in EGT-5. The sun rises at 11:30 where I live. My day starts at 12:30. I eat lunch at 17:00 (aka 5PM). My workday ends at 21:00 (aka 9PM).

Everybody on Planet Earth will have clocks that read the exact same no matter where you are. Everybody on other planets or spacecraft will know what time it is on Earth. Everybody's midday will be a different value on the clock, but it won't matter. All you will ever need to know is if somebody is awake / available between time X and time Y and if you are awake at those same values.

July 19, 2019

https://www.duolingo.com/profile/Neil-VA5WX

The International SpaceStation runs on UTC because it makes sense for them and their international community of scientists and technicians. Launch in Russia, mission comptrollers in Russia and Houston, USA, and downlinks all over the world. Whee!

July 29, 2019

https://www.duolingo.com/profile/Little_Tatws

This would certainly be nice. Everyone would be on the same time and wouldn't have to worry about oddities when you go into another town and suddenly everything is an hour back. Maybe in the future, someday.

July 19, 2019

https://www.duolingo.com/profile/daKanga
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  • 302

ahhh - but then, consider the communities. The diversities of thinking. The rich tapestry of our differences that allow us to see beyond the bare plains of similarity.

Of all the stories we lose when the plain of conformity are forced to lay, to enforce a dream of singularity.

Yet, for there to be held between us, a kindness. An acceptance, yet ney, a celebration of our differences. There I see the greater wealth. Not just of those we live with now. But for the future that extends beyond even our brief butterfly lives.

Understanding, and wealth creation. Sharing and true ability to see the diversity of life, to be shared in a respectful and caring way.

And in that - "Rosetta stones" such as the concept of the UTC, this is dream I hold in esteem.

July 19, 2019

https://www.duolingo.com/profile/dogomolo

This site includes many time tools: timeanddate.com

July 19, 2019

https://www.duolingo.com/profile/daKanga
Mod
  • 302

Thank you for this recommendation dogomolo.

July 19, 2019

https://www.duolingo.com/profile/dogomolo

Easiest way to look up your own time zone: search

what is my timezone

on Google.

July 20, 2019

https://www.duolingo.com/profile/RuwaydaAtH

Nice. Thanks! It definitely will be useful when I go on holiday this summer! ^-^

July 21, 2019

https://www.duolingo.com/profile/toggitang4

Wow that must have took a long time! Thank you for making the GUIDES. They help this community so much!

PS. I'm actually on a great-bumpy voyage so I probably have bad spellimg.

July 21, 2019

https://www.duolingo.com/profile/daKanga
Mod
  • 302

Also I wish you good adventures on your great bumpy ride.
Your spelling looks fine. It is the how and the intent of how we communicate that matters to me. Understanding others minds. Other ways of thinking, and how we function as a community. A world wide community.
How we nurture respect and kindness for all.

Thank you for being a contributor to our community toggitang4.

July 22, 2019

https://www.duolingo.com/profile/toggitang4

Oh okay. The bumpy ride is however over (I did use auto correct ). I'm now on land so it's not bumpy.

July 22, 2019

https://www.duolingo.com/profile/toggitang4

I can tell this post wasn't made from one sitting! My! This is complex I would had have to make drafts for this (if I posted something like this).

July 21, 2019

https://www.duolingo.com/profile/daKanga
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  • 302

This post has been in my head for ever so long. And kept on pestering me.
I still wonder if I can write it in a simpler way. Wondering if there is another way I can split it up. I am still not happy with it.

There is another section to come to talk about days. As of course some of us are on different days of the year. An example of this is that Midnight of New Year falls firstly on those that are in the UTC +14 zone.

Also, when you travel by plane to the East, if you leave from high numbered plus time zone, and land in minus zone, in date and time terms you can arrive before you left. i.e. you cross the date line. It is a curious thing to think about, and also research.

To kick it off, here is an interesting article.
http://www.exactlywhatistime.com/other-aspects-of-time/time-in-different-cultures/

Also of course the interesting concepts that n35w101 has presented in this discussion.

And - I have also had to correct quite a few things - including some spelling errors, and even some errors I have done with numbers. If anyone spots anything, do feel free to shout out - so they can be corrected.

This is also what I love about this community - it's sharp minds. Ever so much sharper than mine.

July 22, 2019

https://www.duolingo.com/profile/toggitang4

Oh no, you should be happy and proud of this! Look! It had helped people and they learned a lot. Now isn't that good? I see that your satisfaction isn't completely full, eh? Well here you still did a wonderful job. :)

July 22, 2019

https://www.duolingo.com/profile/Neil-VA5WX

Your writing was just fine the first time. :)

July 29, 2019

https://www.duolingo.com/profile/the.sheepster

Well ... in the last company I worked at we had UTC-offsets in our signatures since there were so many across-time-zone-teams.

In a gaming community I am in currently, there are so many time zone related issues...

I am just using UTC on all my devices. I calculate the local time in my head by adding one or two hours (depending on DST).

I have just become a total freak about this, but I also use timestamps according to military DTGs...

Best regards,

Daniel, 220816Zjul19

:-D

July 22, 2019

https://www.duolingo.com/profile/daKanga
Mod
  • 302

ohhhhh - that is a fantastic idea, especially for certain communities with certain needs. re:

UTC-offsets in our signatures

July 22, 2019

https://www.duolingo.com/profile/Little_Tatws

You posted this! This is certainly helpful and I suspect I'll need to be using this soon...

July 19, 2019

https://www.duolingo.com/profile/daKanga
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  • 302

Oh MJ, gosh you are balm to so many of us. Thank you for shinning in our community.

July 19, 2019

https://www.duolingo.com/profile/Little_Tatws

Duo13 I should be thanking you. You always have helpful posts.

July 19, 2019

https://www.duolingo.com/profile/daKanga
Mod
  • 302

PST Pacific Standard time https://www.timeanddate.com/time/zones/pst
PDT Pacific Daylight time https://www.timeanddate.com/time/zones/pdt

Los Angles, California, USA

https://www.timeanddate.com/time/zone/usa/los-angeles

-8 -7 Duo31 UTC
16:00 *¹ 17:00 *¹ 00:00
17:00 *¹ 18:00 *¹ 01:00
18:00 *¹ 19:00 *¹ 02:00
19:00 *¹ 20:00 *¹ 03:00
20:00 *¹ 21:00 *¹ 04:00
21:00 22:00 *¹ 05:00
22:00 *¹ 23:00 *¹ 06:00
23:00 *¹ 00:00 07:00
00:00 01:00 08:00
01:00 02:00 09:00
02:00 03:00 10:00
03:00 04:00 11:00
04:00 05:00 12:00
05:00 06:00 13:00
06:00 07:00 14:00
07:00 08:00 15:00
08:00 09:00 16:00
09:00 10:00 17:00
10:00 11:00 18:00
11:00 12:00 19:00
12:00 13:00 20:00
13:00 14:00 21:00
14:00 15:00 22:00
15:00 16:00 23:00

*¹ One calendar day BEHIND the UTC calendar date.

July 20, 2019

https://www.duolingo.com/profile/daKanga
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  • 302

MST Mountain Standard time https://www.timeanddate.com/time/zones/mst
MDT Mountain Daylight time https://www.timeanddate.com/time/zones/mdt

Dallas, Texas, USA

Phoenix, Arizona, USA

-7 -6 Duo31 UTC
17:00 *¹ 18:00 *¹ 00:00
18:00 *¹ 19:00 *¹ 01:00
19:00 *¹ 20:00 *¹ 02:00
20:00 *¹ 21:00 *¹ 03:00
21:00 *¹ 22:00 *¹ 04:00
22:00 *¹ 23:00 *¹ 05:00
23:00 *¹ 00:00 06:00
00:00 01:00 07:00
01:00 02:00 08:00
02:00 03:00 09:00
03:00 04:00 10:00
04:00 05:00 11:00
05:00 06:00 12:00
06:00 07:00 13:00
07:00 08:00 14:00
08:00 09:00 15:00
09:00 10:00 16:00
10:00 11:00 17:00
11:00 12:00 18:00
12:00 13:00 19:00
13:00 14:00 20:00
14:00 15:00 21:00
15:00 16:00 22:00
16:00 17:00 23:00

*¹ One calendar day BEHIND the UTC calendar date.

July 20, 2019

https://www.duolingo.com/profile/daKanga
Mod
  • 302

CST Central Standard time https://www.timeanddate.com/time/zones/cst
CDT Central Daylight time https://www.timeanddate.com/time/zones/cdt

Houston, Texas, USA

-6 -5 Duo31 UTC
18:00 *¹ 19:00 *¹ 00:00
19:00 *¹ 20:00 *¹ 01:00
20:00 *¹ 21:00 *¹ 02:00
21:00 *¹ 22:00 *¹ 03:00
22:00 *¹ 23:00 *¹ 04:00
23:00 *¹ 00:00 05:00
00:00 01:00 06:00
01:00 02:00 07:00
02:00 03:00 08:00
03:00 04:00 09:00
04:00 05:00 10:00
05:00 06:00 11:00
06:00 07:00 12:00
07:00 08:00 13:00
08:00 09:00 14:00
09:00 10:00 15:00
10:00 11:00 16:00
11:00 12:00 17:00
12:00 13:00 18:00
13:00 14:00 19:00
14:00 15:00 20:00
15:00 16:00 21:00
16:00 17:00 22:00
17:00 18:00 23:00

*¹ One calendar day BEHIND the UTC calendar date.

July 20, 2019

https://www.duolingo.com/profile/daKanga
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  • 302

UTC offset for zones in -9 to -12 hours

-12 -11 -10 -9 UTC
12 *¹ 13 *¹ 14 *¹ 15 *¹ 0
13 *¹ 14 *¹ 15 *¹ 16 *¹ 1
14 *¹ 15 *¹ 16 *¹ 17 *¹ 2
15 *¹ 16 *¹ 17 *¹ 18 *¹ 3
16 *¹ 17 *¹ 18 *¹ 19 *¹ 4
17 *¹ 18 *¹ 19 *¹ 20 *¹ 5
18 *¹ 19 *¹ 20 *¹ 21 *¹ 6
19 *¹ 20 *¹ 21 *¹ 22 *¹ 7
20 *¹ 21 *¹ 22 *¹ 23 *¹ 8
21 *¹ 22 *¹ 23 *¹ 0 9
22 *¹ 23 *¹ 0 1 10
23 *¹ 0 1 2 11
0 1 2 3 12
1 2 3 4 13
2 3 4 5 14
3 4 5 6 15
4 5 6 7 16
5 6 7 8 17
6 7 8 9 18
7 8 9 10 19
8 9 10 11 20
9 10 11 12 21
10 11 12 13 22
11 12 13 14 23

*¹ One calendar day BEHIND the UTC calendar date.

July 20, 2019

https://www.duolingo.com/profile/daKanga
Mod
  • 302

UTC offset for zones in -4 to -8 hours

-8 -7 -6 -5 -4 UTC
16 *¹ 17 *¹ 18 *¹ 19 *¹ 20 *¹ 0
17 *¹ 18 *¹ 19 *¹ 20 *¹ 21 *¹ 1
18 *¹ 19 *¹ 20 *¹ 21 *¹ 22 *¹ 2
19 *¹ 20 *¹ 21 *¹ 22 *¹ 23 *¹ 3
20 *¹ 21 *¹ 22 *¹ 23 *¹ 0 4
21 *¹ 22 *¹ 23 *¹ 0 1 5
22 *¹ 23 *¹ 0 1 2 6
23 *¹ 0 1 2 3 7
0 1 2 3 4 8
1 2 3 4 5 9
2 3 4 5 6 10
3 4 5 6 7 11
4 5 6 7 8 12
5 6 7 8 9 13
6 7 8 9 10 14
7 8 9 10 11 15
8 9 10 11 12 16
9 10 11 12 13 17
10 11 12 13 14 18
11 12 13 14 15 19
12 13 14 15 16 20
13 14 15 16 17 21
14 15 16 17 18 22
15 16 17 18 19 23

*¹ One calendar day BEHIND the UTC calendar date.

July 20, 2019

https://www.duolingo.com/profile/daKanga
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  • 302

UTC offset for -3 to -1 hours

-3 -2 -1 UTC
21 *¹ 22 *¹ 23 *¹ 0
22 *¹ 23 *¹ 0 1
23 *¹ 0 1 2
0 1 2 3
1 2 3 4
2 3 4 5
3 4 5 6
4 5 6 7
5 6 7 8
6 7 8 9
7 8 9 10
8 9 10 11
9 10 11 12
10 11 12 13
11 12 13 14
12 13 14 15
13 14 15 16
14 15 16 17
15 16 17 18
16 17 18 19
17 18 19 20
18 19 20 21
19 20 21 22
20 21 22 23

*¹ One calendar day BEHIND the UTC calendar date.

July 20, 2019

https://www.duolingo.com/profile/dogomolo

I made export pdf of three of your latest tables: https://we.tl/t-I8220wUPg3. You should share this file elsewhere because my link is temporary.

July 20, 2019

https://www.duolingo.com/profile/daKanga
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  • 302

Thanks for sharing this. I will have to look into this more at another time, and yes - I have downloaded the file you have created.
Why is your link temporary ?
What are the advantages of having this on a pdf. I do see the advantage of downloading a pdf ?
To have access off line - especially on a portable device - yes - I do see advantages in that.

July 20, 2019

https://www.duolingo.com/profile/dogomolo

pdf is common document format and easy to print. Link is temporary because anonymous file sharing services have such limitations. Also pdf can contain many pages.

July 20, 2019

https://www.duolingo.com/profile/dogomolo

pdf document is easy to place on your desktop for example

July 20, 2019

https://www.duolingo.com/profile/daKanga
Mod
  • 302

UTC offset for zones in +1 to +4 hours

UTC +1 +2 +3 +4
0 1 2 3 4
1 2 3 4 5
2 3 4 5 6
3 4 5 6 7
4 5 6 7 8
5 6 7 8 9
6 7 8 9 10
7 8 9 10 11
8 9 10 11 12
9 10 11 12 13
10 11 12 13 14
11 12 13 14 15
12 13 14 15 16
13 14 15 16 17
14 15 16 17 18
15 16 17 18 19
16 17 18 19 20
17 18 19 20 21
18 19 20 21 22
19 20 21 22 23
20 21 22 23 0 *²
21 22 23 0 *² 1 *²
22 23 0 *² 1 *² 2 *²
23 0 *² 1 *² 2 *² 3 *²

*² One calendar day AHEAD the UTC calendar date.

July 20, 2019

https://www.duolingo.com/profile/daKanga
Mod
  • 302

UTC offset for zones in +5 to +9 hours

UTC +5 +6 +7 +8 +9
0 5 6 7 8 9
1 6 7 8 9 10
2 7 8 9 10 11
3 8 9 10 11 12
4 9 10 11 12 13
5 10 11 12 13 14
6 11 12 13 14 15
7 12 13 14 15 16
8 13 14 15 16 17
9 14 15 16 17 18
10 15 16 17 18 19
11 16 17 18 19 20
12 17 18 19 20 21
13 18 19 20 21 22
14 19 20 21 22 23
15 20 21 22 23 0 *²
16 21 22 23 0 *² 1 *²
17 22 23 0 *² 1 *² 2 *²
18 23 0 *² 1 *² 2 *² 3 *²
19 0 *² 1 *² 2 *² 3 *² 4 *²
20 1 *² 2 *² 3 *² 4 *² 5 *²
21 2 *² 3 *² 4 *² 5 *² 6 *²
22 3 *² 4 *² 5 *² 6 *² 7 *²
23 4 *² 5 *² 6 *² 7 *² 8 *²

*² One calendar day AHEAD the UTC calendar date.

July 20, 2019

https://www.duolingo.com/profile/daKanga
Mod
  • 302

UTC offset for zones in +10 to +14 hours

UTC +10 +11 +12 +13 +14
0 10 11 12 13 14
1 11 12 13 14 15
2 12 13 14 15 16
3 13 14 15 16 17
4 14 15 16 17 18
5 15 16 17 18 19
6 16 17 18 19 20
7 17 18 19 20 21
8 18 19 20 21 22
9 19 20 21 22 23
10 20 21 22 23 0 *²
11 21 22 23 0 *² 1 *²
12 22 23 0 *² 1 *² 2 *²
13 23 0 *² 1 *² 2 *² 3 *²
14 0 *² 1 *² 2 *² 3 *² 4 *²
15 1 *² 2 *² 3 *² 4 *² 5 *²
16 2 *² 3 *² 4 *² 5 *² 6 *²
17 3 *² 4 *² 5 *² 6 *² 7 *²
18 4 *² 5 *² 6 *² 7 *² 8 *²
19 5 *² 6 *² 7 *² 8 *² 9 *²
20 6 *² 7 *² 8 *² 9 *² 10 *²
21 7 *² 8 *² 9 *² 10 *² 11 *²
22 8 *² 9 *² 10 *² 11 *² 12 *²
23 9 *² 10 *² 11 *² 12 *² 13 *²

*² One calendar day AHEAD the UTC calendar date.

July 20, 2019

https://www.duolingo.com/profile/Neil-VA5WX

Thank you! That would make sense, but I'm at UTC -06 hrs, and Duo ends my day at 22:00 hrs local time. I don't understand that logic at ALL! The leagues seem to run on UTC, though, which I can understand perfectly.

July 22, 2019

https://www.duolingo.com/profile/daKanga
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I am sad to hear the difficulties you are having.
I have just checked out my "profile" on Duolingo, and quite a few things have changed since last I checked it out.
Perhaps it is also advisable to check the "region" that your device is set to, in its setup.
What platform do you use to access Duolinogo : (ie Android / iOS (apple) / what browser) ?

July 22, 2019

https://www.duolingo.com/profile/daKanga
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General sundry information about time :

https://en.wikipedia.org/wiki/Coordinated_Universal_Time (UTC)

UTC is the primary time standard by which the world regulates clocks and time.... and is not adjusted for daylight saving time.

All time zones can then express their regions specific time by stating their current offset.
The westernmost time zone uses UTC−12, being twelve hours behind UTC; the easternmost time zone, uses UTC+14, being fourteen hours ahead of UTC.

Current civil time in a particular time zone can be determined by adding or subtracting the number of hours and minutes specified by the UTC offset.

UTC does not change with a change of seasons, but local time or civil time may change if a time zone jurisdiction observes daylight saving time (summer time). For example, local time on the east coast of the United States is five hours behind UTC during winter, but four hours behind while daylight saving is observed there.


I plan to also explain this from some other time zones, such as :

Beijing

https://www.timeanddate.com/time/zone/china/beijing

Melbourne

https://www.timeanddate.com/time/zone/australia/melbourne


*¹ NOTE: Northern hemisphere summer is in the middle of the year.
Southern Hemisphere summer is over December, January, February, etc.
Northern Hemisphere winter is over December, January, February, etc.
Southern Hemisphere winter is in the middle of the year.
Australia is in the Southern Hemisphere.


EDT can also be expressed as UTC−05. Expressing it as UTC-05 is very useful, as it tells you and others that you're current time zone is 5 hours behind UTC time.
During daylight savings EST is UTC-04. ie it is 4 hours behind UTC.


The Eastern Time zone is roughly a triangle covering all the United States from the Great Lakes down to Florida and east to the Atlantic coast. This is also the time zone that Duolingo HO is in.

July 22, 2019

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Getting the day of the meeting right

ok, now we need to talk about deciphering a date. And how to work out what it means to you in your time zone.

Again, we will use the example of Pittsburgh.
We know the UTC offset is -4 for summer time, and -5 for winter. That this year they will change time zones on at 2:00am Sunday 3 November, 2019.

In the table in the header, you will notice I have highlighted some times.
ie.

-5 -4 Duo31 UTC
19:00 *¹ 20:00 *¹ 00:00
20:00 *¹ 21:00 *¹ 01:00
21:00 *¹ 22:00 *¹ 02:00
22:00 *¹ 23:00 *¹ 03:00
23:00 *¹ 00:00 04:00
00:00 01:00 05:00

*¹ One calendar day BEHIND the UTC calendar date.
These are the ones for those in Pittsburgh, that you have to do one other slight thing when either converting to UTC to share, or converting from a UTC date and time back to your own time zone.

It only concerns these UTC times between UTC 00:00 and UTC 04:00 for those in Pittsburgh.


Lets assume someone tells you they will do something, or wish to contact you on :
UTC 2nd November, at 00:30 . The standard notation for this is UTC 2019-11-02T00:30

So you know timewise that will be at 19:30 (7:30pm) your time.
However which day ?

Because Pittsburgh is between -4 to -5 hours behind UTC, depending on the time of year, this is referring to one calendar day earlier. Being that the event/meeting/etc will be on 1st November Pittsburgh time, not on the 2nd.


If another event is scheduled for UTC 3:00 on 2nd November, once again the event will fall on 1st November at 23:00 Pittsburgh time.
An event falling on UTC 2nd November at 4:00, will mean it occurs at midnight at the end of 1st November, just as 2nd of November starts in Pittsburgh.


While UTC 2019-11-02T05:00 will be the 2nd of November 2019, (the same calendar day) at 1:00am in the morning Pittsburgh time.


Lets move on to one day later, when the clocks change. The clocks change for Pittsburgh at 2:00am in the morning of 3rd November 2019.

At 1:00am on 3rd November 2019 in Pittsburgh, the equivalent UTC time and date is UTC 2019-11-03T05:00, as the clocks still have not changed. Note both Pittsburgh and UTC time is on 3rd November 2019. In Pittsburgh it is is 01:00, while it is UTC 05:00

At 2pm on 3rd November 2019, the clocks change back to 1pm, Pittsburgh changes time zones from UTC-4, to UTC-5.
At 1 minute to 2pm, just before the change, the UTC time is UTC 2019-11-03T05:59

As 2pm occurs in Pittsburgh, Pittsburgh time changes to 1pm. UTC remains constant and becomes UTC is 2019-11-03T06:00


That evening of the 3rd November 2019, at 19:00 Pittsburgh time, the UTC time is UTC 2019-11-04T00:00. UTC time has now moved on to 4th November 2019.


By 23:00 Pittsburgh time on 3rd November 2019 UTC time is UTC 2019-11-04T04:00
When Pittsburgh reaches midnight on the 3rd November 2019, it is UTC 2019-1104T05:00. And Pittsburgh also changes to the next day of 4th November 2019. Both Pittsburgh and UTC time is on the day of 4th November, 2019. However it is 00:00 hours in Pittsburgh on the new day of 2019-11-04, and UTC05:00

July 22, 2019

https://www.duolingo.com/profile/daKanga
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To see the tables for Time zones in the USA, and also used by some other regions in the Americas, click on the links in this table.

Description End-Start year Mid Year Duo31
USA-PDT/PST -8 -7
USA-MDT/MST -7 -6
USA-CDT/CST -6 -5
USA-EDT/EST -5 -4

*¹ Returns you to the header of this post, where you will find the table for USA-EDT.

UTC offset time zones for -4 to -8

July 26, 2019

https://www.duolingo.com/profile/Trubby1

It’s really just GMT (Greenwich mean time) but the french and others didn’t having to follow U.K. time, so they used the need to amend it by a few micro seconds as an excuse to rename it

July 21, 2019

https://www.duolingo.com/profile/daKanga
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hmmmm - from my reading and research it is a tad different to that. Such as how FranM2 has explained it here

Also, one can have enormous fun with this concept. In a wonderful and impressive tiny town in deepest darkest rural France, every year they have a "Festival D'Astronomie" at La Chapelle aux Lys [85]

Last year a very special event happened, as declared by the town Mayor.
It inaugurated its very own meridian line on Sunday August 2019 ! Leaving the meridian of Greenwich.

In the village of La Chapelle-aux-Lys, in the south of the Vendée, the time is now delayed by 2 minutes and 38 seconds on the meridian of Greenwich. However Philippe Boisson, the mayor of the town, reassuringly declared: "This decree will not change anything for us. We will not apply it literally. We have just decided to create this meridian to celebrate the 10th edition of Astrolys, our festival dedicated to astronomy. This decree is a joke ... We are doing astronomy with a bit of humor so that people remember. "

It always impresses me when even such small communities do things of such significance.

Here is an article, in French, that goes into this in more detail. https://www.franceinter.fr/sciences/la-chapelle-aux-lys-en-vendee-a-desormais-son-propre-meridien

July 22, 2019

https://www.duolingo.com/profile/dogomolo

What do you think about this site duolingo.fandom.com/wiki/Duolingo_Wiki?

July 29, 2019
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