After a relatively weak monsoon across the southwestern U.S. in 2019, expectations were high for an active 2020 monsoon season. Unfortunately, the opposite happened and June through September precipitation totals were record low for many stations across the region. The summer was also the hottest on record for many locations. This presentation will provide a basic background of the climatology of the North American Monsoon System with respect to shifts in circulation patterns, moisture sources, and patterns of precipitation. A comparison of conditions between 2019 and 2020 and examination of circulation patterns that may have contributed to the record dry precipitation levels in 2020 will also be discussed.