University of Arizona
Backyard Gardener: La Nina Weather Conditions Jan 2000
This site by Arizona Cooperative Extension discusses the strong trade winds called "La Nina," and how they effect the climate.
University of Arizona
The Arizona Monsoon
This site explains the monsoon pattern that affects Arizona. It explains the cause of a monsoon and lists some of the monsoon data gathered since 1896. It also has some safety information related to lightning.