The weather is usually hot, in Thailand and anywhere in Southeast Asia.
But every Southeast Asian country has locations where the climate is especially unbearable, and where it is more comfortable.
But that is not where foreigners usually end up. Foreigners relocating to Thailand or Southeast Asia in general usually have a local wife. And as their relationships solidify, foreigners typically are drawn into living at their wife’s place of origin.
Anyway, she has her parents there.
But you have a good reason not to live at the place of origin of your wife. Actually, you have several good reasons, but most of them, you better keep to yourself.
The one reason that you do not have to keep to yourself, and that you can bring up again and again, is uncomfortable weather.
And heat can be uncomfortable. Really uncomfortable.
Where to stay?
Look at a map. Comfortable places in Southeast Asia are almost always in the mountains.
And not only do mountains protect from uncomfortable climate. They also do a job, to a certain degree, to keep out shitty modern culture.