Anyone been on a trek in Xishuangbanna? What did you find worked best in terms of clothing / equipment? Thinking of taking walking trousers, walking boots and long-sleeved top, with waterproofs in bag. Wondering what other people's experiences were in terms of the heat / rain? (Going mid August).

Is it just normal shorts, t-shirts, sandals in Kunming / Dali / Lijiang etc with raincoat and umbrella?

Dali/Lijiang and Kunming (to a lesser extent) can get cold all year round, particularly at night or when the sun isn't out. They are at a high altitude, so when the sun ain't shining, the altitude takes over temperature wise. Banna is pretty much full on tropical so no worries there.

Lijiang for sure can get cold at night. I think layering works best in Yunnan wide travel. Banna will be hot humid after the tropical depression has passed.

I just got back from a week in Xishaungbanna and Mengla and it was plenty warm. I didn't bring long sleeves or pants and didn't need them, except maybe to save me from a few bug bites. It got a little cooler at night while I was staying in the tea mountains closer to Laos, but still didn't require layers or long sleeves. Be prepared for rain. It might not last long, but if you're caught without shelter, you'll be soaked. If you've been anywhere tropical during the wet season, you'll have probably experienced it before.

Disclaimer: I'm Canadian and nothing feels cold to me in this province, so it's probably relative.