did I miss the lesson where they did future tense?

I don't see why "tomorrow will be hot" is not an acceptable translation. Hot seems like a perfectly good translation

@yah511 No but it's very simple, you can just Google it and probably get the basics of the tense down in like, 10 minutes. (Also I'm having problems with the DL app on mobile, replying to people, maybe someone check this?)

"there will be warm tomorrow"---can't I say so? why?

Я надеюсь.

How would you say "Pretty much everywhere it's gonna be hot"?

Тепло apparently can be either an adverb ("warmly") an adjective ("warm") or a noun ("warmth").