Wow, we have a lot on internet, you could read it here:
http://www.usingenglish.com/reference/idioms/cat/4.html
However here is the most common idioms about weather that I know.
- Feeling under the weather. It means you are feeling sick.
- a cloud on the horizon. When you see a cloud on the horizon, it means you see something bad, of difficulty is coming. A problem is predicted or likely to arise in the future.
-On cloud nine. You are on could nine, it means you are very happy because something fortunate happened.
-Come rain or shine. It means a person will do something whatever the circumstance. For ex: I'm gonna study English come rain or shine.
-Fair-weather friend: It means some one who acts as a friend when times are good, and not there when you are in trouble
-The lull before the storm. The unnatural calm before a difficult time or violent activity
- Chasing rainbows. When you trying to get something that you are never obtain. When a person tries to get something she/he can never obtain.
-Raining cats and dogs. Extremely heavy rainfall. for ex: Our trip was canceled because it was raining cats and dogs.