Below ground weather occurs below the earth’s ground surface and in cave regions that are below ground elevation. The temperature of the air has an influence on the temperature below ground but that influence decreases with distance below the ground. The air at the surface and the earth’s ground surface exchange heat when the temperatures are different. Warm ground will help warm the air and cold ground will help cool the air. Warm air will help warm the ground and cold air will help cool the ground. This can have a significant influence on freezing rain precipitation events since the ground surface can be the decisive factor that determines if it is cold enough for rain to freeze or not.

Basements are influenced by below ground temperature. In the summer, the ground several feet below the surface can be much cooler than the hot air above ground. This can provide a natural air conditioning to the basement. In the winter, the ground can be warmer which provides a natural heater for the basement.

The weather within caves is often very different than the weather outside. The weather in the caves tends to be more uniform than outside. The amount of water flowing into the cave will influence the humidity levels. The temperature tends to be moderated since sunlight cannot warm it up to high temperatures and the rock tends to not be frigid.

The diagram below shows the reduced influence of weather in the air with distance below ground and the weather in a cavern (less extreme and generally cool).