The Arizona Monsoon Season is from June 15 thru September 30, according to the National Weather Service in Phoenix, AZ.
Monsoon Rainfall For Phoenix
Wettest Monsoon Season: 9.56 inches in 1984
Dryest Monsoon Season: 0.35 inches in 1924
Average Monsoon Rainfall: 2.71 inches
2013: 2.99 inches
2012: 3.00 inches
2011: 1.60 inches
2010: 2.48 inches
2009: 0.87 inchies
2008: 5.70 inches