Mountain Streams, the Atlantic Ocean in New England...
...and my pool. They're all about the same temperature. Fortunately, having grown up swimming in really cold water, it feels great!
One of the questions that I get all the time, but especially during the summer, is whether wearing a scarf makes me hot. Fact is, everyone is hot when it's 95% and 95% humidity, scarf or no. Other fact is, your body adapts. People who live in cold climates can walk around in flannel shirts when the rest of us are wearing parkas. People from hot climates walk around in parkas when the rest of us are wearing shorts. The internal thermostat of women who wear hijab adjusts itself so that we don't overheat. (After all, if it didn't, you'd see lots of women passed out on the sidewalk from heat stroke!)
One thing I have wondered about though, if a woman wearing a scarf doesn't have to work as hard to keep herself warm, does that mean her body isn't burning as many calories, and it's harder to stay thin?
I think I'm grasping at straws...