People urinate more during harmattan because of lack of sweat secreted. It is expected that you drink more water as you urinate during this harmattan and also exercise your body if you're not comfortable with urinating all the time in order to sweat which is good for the body.

This happens during cold rainy days too.

I ain't a doctor tho but I think it's because we humans drink more water during this period.

Good one op

@ Skillfullulu, observe it very well. We dont get thirsty all the time during the Harmattan and that is why our skin tends to break n whitish cos of the lack of taking or inadequate n inconsistent drinking of water.

To me people urinate more during the rainy seasons

On a cold day, the cold sensations from the environment would first be received by the cold sensitive nerve cell endings of the skin which will in turn send the message to the part of the brain that is responsible for the temperature regulation of the body. The part of the brain that is responsible for this is the HYPOTHALAMUS. In response to the message sent to it, this hypothalamus part of the brain then causes what is known as VASO-CONSTRICTION to take place i.e the blood capillaries under the skin will be made smaller so as to allow for less flow of blood. The result of this is that it leads to less sweating on the surface of the skin and there will not be a chance for evaporation and cooling. If your pores are not so opened and there are no sweating, water cannot be lost through the skin hence leaving you with the sole option of urinating. This is why people urinate more on a cold day or in a cold room and less on a hot day.