I visited Austin in the summertime and after a day of 100+ humid weather, the evenings go down to the lower 80s/upper 70s. It felt like a jacket or a light windbreaker would’ve been needed.

And this is coming from someone who normally lives in California. I guess the body adjusts to the climate of the region after a couple days.

People get acclimatized to their environment.

I'd eat popsicles in Hong Kong falls and winters because I've long since adjusted to the cold.

After a few weeks in a very hot place, your body adapts and you get used to it. If the temperature that day suddenly drops 20 degrees to 81, you might need a sweater.