On Oct 20, 8:57 pm, Terence Wilson wrote:
I'm confused about what determines the local altimeter setting. My
understanding is that there is a barometer in the tower that measures
the weight of a column air extending up into the atmosphere. What
factors affect its weight? Is it purely temperature variations caused
by uneven heating by the Sun or is there something else?

In a similar vein, I understand that winds are caused by pressure
discrepancies which lead to winds moving from high to low pressure
areas. Again, are the pressure differences caused by temperature only?

Thanks.

Uneven solar heating is the primary cause of all weather on earth.
There could be other sources, such as fluctuations in the earth's
magnetic field and gravity of the moon, but solar heating is the
primary source.