I have been seeing today written as "idag" and tonight as "ikväll", but here it is "i dag". Is that a regional thing, or is the joined version just slang and therefore this is the correct way?
Both are correct, but the language council recommends "i dag", "i kväll" etc.
Tack för det snabba svaret :)
so would "i dag" and "i natt" basically mean today and tonight?
Won't need that, it never rains in Sweden.
What is the i for in i dag or i natt?
Basically the same as the "to" in "today".
Could this also be taken as "It rains this day"?
It's the same meaning but not a translation.
How do I say it rained instead of rains?
That is regnade.
I'm welsh so this is useful
The Welsh course is quite fond of Mae hi'n bwrw glaw and similar. You'll fit right in. :p