It is not uncommon in Arizona to be driving around and then hit a sudden downpour of rain that makes you feel like you are in the midst of a hurricane. That my friends is called monsoon season. During the monsoon, or summer thunderstorm season, Arizona experiences more severe weather than many other states. On rare occasion, a severe storm may spawn a tornado. More often, high winds, dust and severe downpours resulting in flash floods are common monsoon occurrences. Monsoon season starts June 15 and lasts til September 30.