For example, my best friend and I both live and were raised in the same area, and thus grew up in the same climate. She is always colder than I am. At 75º I feel great, perfectly comfortable. She is cold, needs a sweater.
When it comes up in converation, people usually just say it’s that we have different metabolism. What I want to know, what is different? Why is it different?
This is a good question. I have a friend, a really good friend, who I can’t get together with if it’s really hot because she hates hates hates hot weather and I love it. (I am always colder than everybody.) We can’t get together because she doesn’t want to bitch about it, knowing that I enjoy it, but she can’t really think about anything else.
We have blamed my California upbringing but I don’t think that’s it.
My wife and I are like this. It’s so bad, there can be times when she is shivering and I am sweating.* We’ve speculated it has to do with the temps our respective parents kept the AC at when we were kids (My parents: 65, Her parents: 80) but I’ve never been confident about that.
-FrL-
*Her present to me for my birthday one year? A blanket for her.
Part of it may be related to surface-area-to-volume ratio.
IMO it’s the presence or absence of a Y chromosome, respectively. You’ll note in all three examples above it is the women who are cold. I’ve seen it in every office I’ve worked in, women walk around in cardigans and sweaters, men in short sleeves.
It seems to me that women are never warm unless actually in the act of baking in the tropical sun, or snuggled up in bed under three layers or more.
Yes, rampant generalisation, but a surprisingly true one in my experience.
In Hilarity’s post, the one who doesn’t like hot weather is female.
In my case, the one who doesn’t like hot weather is male.
-FrL-
The woman being cold/men being hot thing is always strange to me, because I used to be one of those person who was turning up the AC in November, keeping the windows open in the middle of winter. In the last few years, I’m completely the opposite, always needing to be warm, etc. (And a woman.) Am I hermaphroditing out or what?
I grew up in Alaska but have lived in California for a long time now, and I’m perfectly happy at about 70º. On the other hand, I’m the hottest person I know. 
I’m always shocked when I shake hands with someone in the winter and notice how unbelievably cold their hands appear to be compared to mine.
In my experience, people who are overweight tend to be less able to tolerate heat, while thin people tend to always be cold. Regardless of gender.
But I’ve known exceptions to this, as well.
I couldn’t take the heat when I weighed 110 lbs in high school, and was never cold, and I’m the same now at 200 lbs.
I have frequent hot flashes nowadays.
They SUCK.
I’m sitting around, sweating like hell, just about all the time.
I’ll be so glad to be finished with this evil, EVIL menopause thing.
That time can’t come soon enough.
They all detest me at our house. The a/c is set to a constant 62F, and sometimes, that’s even too warm for me. Everyone sits around all covered in throws or blankets, and they actually have the nerve to wear sweats and long sleeves!
Babies.
Take into account that people get circulatory problems. They are cold in a warm room. The onset of arthritis will modify their tolerance of cold also.
I’m the other way round - my hands and feet are often freezing to the touch (although they don’t feel cold “internally” to me), while I feel perfectly warm within myself. I wonder if it’s a circulation issue - some people’s bodies are more efficient at redirecting blood flow to the core of the body, which keeps the body temperature up at the expense of anyone they happen to touch?
Exception checking in. I’m quite plump and always cold.
twicks, female, thereby proving the other stereotype in play
Differences in circulation.
That and there is a large psychological component. Kids tend to not noticed minor changes in temperature, but as we grow up we get more aware of heat and cold, and tend to become set in our preference (unconsciously of course). I think I read an article somewhere about how you can learn to reset your preference and learn to ignore minor temperature differences (10-20 degrees, not like 1 or 2).
For myself, sometimes when I become acclimated to certain working conditions, say high heat working conditions in the summer, I don’t mind 75-80 degrees, but when I work in a place that is air conditioned all summer (say 65-70 degrees, yes, my last job was 65), I got hot at 70+ and had difficulty standing anything higher.
I say Acclimation.
I’m not plump, female, and always overheating. Summer is my absolute least favourite season. I love winter. I love autumn. It’s nice and cold. Mr. Lissar is the one who freezes and wears layers of fleece.
I think medication can play a role in it too (possibly just in relation to circulation, though.)
My dad’s on some kind of meds now that makes him walk around the house with a winter hat on.
When I moved back from Korea where it was actually cold I would walk around in shorts year round in California but after 5 years i started to need pants and sweatshirts. I then moved to Colorado and got poor, college, and so could not afford heat in the winter so after two years of that i move back to California and now I am always hot since year round shorts are no longer an option. I vote for acclimatization although I did put on a 100lbs in college so I’m sure there is an insulating factor as well.
It is not necessarily fixed - my temperature preferences have changed over my life and depending on location.
I used to never feel the cold. My folks kept the house around 20 degrees Celsius, and all through (Canadian) winter I would leave my bedroom open and walk around in jeans and sneakers and only complain when it got to minus 20 or so out.
Then I married an African, a skinny one to boot. In the winter he wore three pairs of pants (indoors, starting in November) and couldn’t get the inside temperature warm enough, and slept under piles and piles and piles of blankets, sweating happily.
I never got quite to that point, but I certainly started feeling the cold a LOT more when I was living with him. No longer do I leave my bedroom window open all winter and I now have several sensible insulating undergarments that I hadn’t even considered in the past.
It also depends on the type of cold. In England a number of people said to me “You Canadians always complain about the cold in this country!” Because it’s a different cold than what I’m used to: damper, for one thing, and my usual coping techniques (plentiful hot baths, central heating) weren’t available. So often I felt colder than in Canada, even though the actual temperature was probably higher.
My wife is half-Lebanese, I’m a tubby Irish guy. We grew up within 10 miles of each other and in 14 years we have never found a temp that’s comfortable to both of us. I just figured it was a chick thing and never worried about it.