Weather spells are an ambiguous topic. It is extremely personal magic. My desire for a beautiful sunny day may correspond to your need for rain. Will our spells cancel each other's out? Does the most powerful magician win?
Despite these inherent difficulties, Weather Spells are among the most ancient magical genres. The most successful weather spells are cast by a community in response to a consensus regarding a weather emergency, typically either too much or too little rain. It was believed that one could summon or banish storms by invoking ancient spirits. In essence the storms and winds are spirits.
This belief remains personified in the orisha Oya, who embodies the hurricanes that travel from West Africa to the Caribbean annually. Vestiges of these beliefs linger in the tradition of naming hurricanes, by naming the spirit, a measure of control is maintained.
Magical and spiritual aspects of weather have always been controversial:
- Ancient Mesopotamian wind spirits could be destructive, as can the modern Central American "Aires."
- Jews perceived winds as messengers of the Creator, although not all are inherently benevolent.
- In the Odyssey, Odysseus is given a bag of winds as a divine gift, sealed up with knot magic. When his curious men release the knots too soon, the gift turns to disaster.
- According to Saint Thomas, wind and rain could be produced by demons. Hence magicians who offered to sell storms to those who needed them.
- The earliest ecclesiastic law in England, the Liber Penitentiales of Saint Theodore, Archbishop of Canterbury from 668 through 690, was directed against those who caused storms by invoking "fiends."
Source: The Element Encyclopedia of 5000 Spells