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?

Won't need that, it never rains in Sweden.

Could this also be taken as "It rains this day"?

so would "i dag" and "i natt" basically mean today and tonight?

What is the i for in i dag or i natt?

How do I say it rained instead of rains?

I'm welsh so this is useful