Seasonal variations in Earth's climate are caused by

The earth orbiting around the sun.

Explanation:

Before reading this explanation please bare in mind that the earth's axises are tilted and not in one straight line. Now as the earth orbits around the sun it is subjected to different angles each and everytime these different angles result in different amounts of sunlight striking the earth therefore the temepratures will differ changing the cimate and these changes are seasonal, we have four of them and they are known as our four seasons

i'm pretty sure it's spores

relative humidity, temperature and dew point -- are bound together in the mathematical relationship below. relative humidity changes when temperatures change. because warm air can hold more water vapor than cool air, relative humidity falls when the temperature rises if no moisture is added to the air. so i would say a