I'm probably doing something silly and obvious, but oh well:
When I first joined Duolingo I was living in Ottawa. Now I live in San Francisco, which is exactly 3 hours behind :P
How do I change my timezone? Can't find that setting(?), and both my mobile device and laptop have the correct timezone at OS level.
For whatever reason, the "timer" for streaks still starts at 9pm for me instead of midnight. That is to say, I need to meet my "daily" goal in 24 hour periods that start at 9pm at night and end at 8:59pm the next day.
Or is the entire Duolingo universe on Eastern time when calculating streaks?
Your timezone is set when you first register and Duo gives no way of changing it. There is a user script which does let you change your timezone although I have never tried it myself so do not have the link so maybe someone else can give you that.
Otherwise it's a case of getting used to your Duo day starting at 9pm to 8:55pm the following day
Then your only other option is to creat a new account from the timezone you are currently in. Unfortunately you cannot transfer your progress from one account to another but you should be able to test out of skills in your new account so you are approximately back to your current levels.