We could post the link to the pages showing the average temperatures and precipitations for various places in Thailand, but I'm afraid everybody would keep on asking What's the weather like in August in Pattaya?

For instance :

Bangkok
Phuket
Chiang_Mai
Pattaya
Koh_Samui
Hua_Hin
Udon_Thani

Strangely there isn't Krabi, but we can assume the same weather pattern as Phuket....