As has been mentioned it is rainy season in SE Asia, but those are the torrential showers that 20 minutes later have dried up totally.
My favourite place on the planet is Hoi An, Vietnam, we stayed in the Victoria Resort and loved it. Also did Hue (very historical but not very nice), Hanoi and Ho Chi Minh City on that trip.
In Thailand have been in Bangkok (loved it), Hua Hin (loved it), Pattaya (hated it) and Chiang Mai (loved it).