What affects weather?
Weather changes basically due to differences in temperature and moisture of different places. It also depends on wind. Weather also changes due to sun rays falling in various places.
For eg: the sun rays fall mostly in the equator so the weather in the equator is hot.
Surface temperature differences in turn cause pressure differences. Higher altitudes are cooler than lower altitudes as most atmospheric heating is due to contact with the Earth's surface while radiative losses to space are mostly constant,
For more information, click on : Introduction to Weather and more