I’ll take the 90 f anytime. 66 sucks.
Upper 60s are my favorites - I can leave the house open, I’m comfortable outside, it’s not usually gawd-awful humid - what’s not to like?
It’s closing in on the upper 70s here right now and the humidity is about 9000%. I had to close the house and put on the air. How much longer till autumn??
I choose to vacation in Las Vegas in late July/early August almost every year. And I hike in the hills more than I hang out in the casinos.
I was born to live in the tropics, for years I was sure that my parents stole me as a child but since my son is the absolute reincarnation of my father I guess I was just born to be tortured by snow.
I’m perfectly comfortable at anywhere between 27 and 40. The only time I complain about the heat is when the dogs decide to play blanket.
I must be a ‘polar bear’ because above 80f (26.6c) my brain starts to shut down.
66f (19c) is a great temperature for me. After all, you can always put on more clothes, but there is a limit to how much you can take off.
I really hate this too. When I go to a hot country, I am going to be dressed for the heat, in a T-shirt and possibly shorts. Please do not turn all public buildings into refrigerators!
Uhhh…how long do you intend to remain Unwashed? 
Oh man. Me too. I sat at a bar in Florida a few years back and could barely finish my lunch I was shivering so badly.
Depends on the coast, I suppose. Gulf Coast temps in the summer are routinely in the mid-upper 80s and low 90s.
As for me, 66 over 90 any day. 90 is doable in the shade if it’s not too humid, or there’s a breeze. There’s not much you can do other than wear shorts and short sleeves and hope that you don’t have to do any exertion or be in the sun much.
66 though, is fine at any weather- if it’s sunny, you wear short sleeves, and if it’s overcast and windy, you wear a windbreaker.
Oh… 90 is NOT brutally hot unless you’re in the UK or Norway or somewhere like that. 90 is basically on the hot side for a spring day around here. 95-105 is normal summer heat. Anything over 105 is brutally hot by my reckoning (we’ve seen 108-112 several times in the past decade)
AC temperature is one place where two groups of people will have to agree to disagree. I know people who carry sweatshirts around in Florida. But IMHO the AC may get cold sometimes, but is infinitely preferable to sweating or carrying around a sweatshirt that you use 1% of the time.
These aren’t constantly frozen though. The summers can be muggy in these places, and parts of Norway are also bright for long periods, so sleeping can be rough. I live about 12-20 degrees south of them, in a desert, and winter lows are still just 1-4 deg (F) higher than Oslo.
66 is better than 90 but 72F and no breeze is perfect.
My Unwashed state will last as long as I do 
Maybe I should be arguing for a below-freezing temperature for the sake of those around me?
When I was in college, I noticed strange reactions to the same temperature. The first sunny 66 degree day in the fall would bring out people in sweaters and sweatshirts. The first sunny 66 degree day in the spring would bring out co-eds in bikinis, trying to get a tan.
I suppose I could have gotten used to either temperature for the long term when I was younger, but I think the 66 degrees would be easier to deal with now.
- The only thing 90 is good for, as others have said, is swimming. I HATE hot weather.
I like having four seasons but I wouldn’t mind if the spring/summer part never got over 70. 90 is uncomfortable when it’s dry and unbearable when it’s humid.