You mean aeromancy?
Aeromancy comes from the greek word "aero" which means "air", and "manteia" which means divination. It is basically divination by observing events in the air or wind. Including cloud shapes,weather conditions,rainbows,change in weather patterns,storms,and pretty much any atmospheric phenomenon.
Due to the intrest mankind has in weather, it is no suprise that it is one of the oldest forms of divination.The heavens were seen as the link between the gods and humanity, in which the gods expressed their anger or joy toward humankind.
Some different types of Aeromancy are:
Eromancy: Taking omens and signs from the air.
Austromancy:Divining by winds and cloud shapes.
Anemoscopy:Divining by wind speed, direction,the sound of wind, or certain objects being blown by the wind.
Nephomancy:Divination by studying clouds and their colors,shapes,and positions in the sky.This practice was called "Neladoracht" by the ancient druids.
Chaomancy:Looking for visions in the sky such as cloud formations and the stories they may tell by those shapes.
Ceraunoscopy:Divining by thunder and lightning.
Brontoscopy: Divination by listening to the sound of thunder.
Roadomancy or Astromancy: Divination by studying stars, comets,and meteors.
Cometomancy: Specifically divining by comets.
Meteormancy:Specicically divining by meteors.