Originally posted by honeymouse:
Since you don't sweat when you are feeling cold, the only way to eliminate the "waste" and excess water from your body is through urinating. Hence, it is normal to urinate more frequently when you are feeling cold.
When you sweat a lot you will realise you don't go to the toilet as much. If you drink enough water, your urine should be light in colour and opposite if you haven't drunk enough water.

erm... This is not what's happening in the body...
To give you a general idea.
In a cold area, your blood vessel will constrict the reduce heat lose. As BP = cardial output (your blood volume) x Peripheral resistance (your blood vessel area). Your blood pressure(BP) have to maintain and your peripheral resistance increased due to the constriction. The only way to keep BP maintained is to reduce your cardial output. Your blood volume contains red blood cells , water and so on. So, water is removed to reduce your cardial output. Therefore, your blood pressure is maintained. The excess water will then be removed by urinating.
cheers.