Which one is correct and why?
1. I won't travel until it will be warm enough.
2. I won't travel until it be warm enough.
3. I won't travel until it is warm enough.
1 is incorrect because we don't use future structure in a time clause.
However I couldn't find any reason for rejecting either 2 or 3.
3 is correct. We use the simple present there, not some sort of subjunctive "be."