Temperature variation is the cause of most weather phenomena and is a major factor in aircraft performance. Warm air expands and cool air contracts, thus changing the densities of the air. At higher temperatures reduce air density which reduces aircraft performance.
Diurnal and topographical temperature changes create local winds; such as sea, land, mountain, and valley breezes. Diurnal cooling can lead to the development of fog, which can impact visibility.
During the winter months, temperature plays a vital role in which form of precipitation can fall in a particular area. If precipitation falls in the form of freezing rain, it can cause icing on the wings, which is extremely dangerous.