I would think any temperature under our natural body temp would feel cold. To take it further, I live in the north, so 75 can start feeling hot to me, yet people in the south might consider that chilly. We both have the same body temp so how does that work?
In: Biology
As simple as can make it, you feel temperature by “taking” or “giving” it. So it depends on how fast something can take or give it, and how much temp there is. Metal gives/takes it really fast, so you’ll feel whatever temperature it is really easily.
Our skin is okay at taking or giving, but water is even better at taking/giving, that is why your body sweats when it needs to cool off. It puts water on you, so that your skin will give some of its temperature (also why wind helps as the air is moving so your giving heat to it constantly rather than stagnant wind).
Or like a thermos, the outside coating can be kind of whatever, but, the insulation is really slow at taking/giving, so it won’t give or take it from the liquid inside as quickly as lets say if it was made of just metal.
There’s more detailed explanations, but, that is basically the way it was explained to me,
To the second point, your body just gets used it. My friends keep their houses at like 70, but, my house is 80. When I first walk in, it feels chilly, but, after a bit your body regulates itself to the temperature difference. Like jumping in a cold pool on a hot day, cold at first, but, after your body figures connects the dots and starts doing some internal regulating its not cold anymore. (not counting extremes, which you can work towards, but, jumping in 10 degree water will be cold for much longer and needs a lot more regulating and is debatably unhealthy)
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