I wore my Poncho Burnt Orange short-sleeve ("The 1969") shirt all over Japan during their normally-really-humid-with-no-wind (80-95F days with 80%+ humidity, and no wind during daytime) summer this year, including on Okinawa where it was 90%+ humidity day and night, and it was nails. I grew up in the Houston area, so though it never did the 100F+ with 70% humidity that I became so familiar with in Houston, the shirt held up great.
After washing it, whether I stayed at a place that had a clothes-dryer hot-air blower over in the shower-bath room (like many homes/apartments in Japan have) or I just hung it up to air-dry inside, my Poncho shirt was always the first thing dry, before my Dri-fit Nike workout shirts were dry.
And yes, the Poncho short-sleeve shirt is lighter than the regular Nike Dri-fit shirts.
Like others have said, I have bought some more Poncho shirts in different colors, too.