Temperate (comfortable) places/times of year for SE Asia

[Boxman]

I've finally saved up enough money and setup enough cash flow from my rentals that I can quit my day job and start traveling. I plan to explore SE Asia first (southern China, Phillipines, hopefully Vietnam & Malaysia also, depending on circumstances). Like everyone else, I enjoy temperate, moderate weather without overwhelming humidity and temps below 85 F or 30 C. I'm guessing this dictates travel from October thru March. What regions of these countries do you recommend? Don't need huge cities just decent #'s of the opposite sex to be present, so remote villages are probably out.

Anyway, the adventure begins soon!

Any suggestions? Any and all advice (and not necessarily just about the weather) are appreciated!