In Chapel Hill, the temp just now is 56. The wind is north at 5 mph, and the humidity is 56%. We should arrive at 59 before the day is out--not exactly sweaty.
To take advantage of any perkifying effects, however,it's important to actually step outside one's door.
A sobering detail from Science Daily:
"...People in industrialized countries, on average, spend 93 percent of their time indoors, making them largely disconnected from the impact of changing weather outside."
The Science Daily article seems to favor warm weather, BTW. Perhaps the researchers are based in Lake Wobegon. I for one am emboldened by crispy air.