"Your body temperature is about 37C or 98F depending on which side of the Atlantic you are. If you are like most people it "feels" quite uncomfortable when the temperature outside is 37C. When asked most people say they like 20-27C (or 65-80F). "
The basic point is that our body is constantly producing heat. In fact, most of the food we eat is eventually converted to heat. This should explain why the average daily intake of an adult is approximately 2500 calories, while only about 300 of those are consumed by jogging for 30 minutes.
For heat to flow, it needs a temperature difference. Thus, the 10-12 celcius difference that a 25 celcius environment provides, enables us to efficiently dissipate the heat we constantly generate. This leads us to the answer.
Our skin senses heat flow (flux), not temperature.
There are several manifestations which illustrate this point:
- When you sleep, you feel colder because your body processes have slowed down, producing less heat.
- When it is hot your body sweats. Sweat vaporizes, and in doing so takes away a lot of heat from your body (aka latent heat of vaporization).
- When it is windy you feel colder because heat is being convected away from your body faster (the wind chill effect).