Since the water year began on October 1, New Mexico and parts of Arizona have been much drier than average (Figures 2a–b). The La Niña circulation pattern, which helped deflect winter storms to the north, affected both states by reducing precipitation. New Mexico also experienced a below-average monsoon as a result of the position of the subtropical high—generally parked over New Mexico—which kept skies clear and brought little moisture to the state. Arizona, on the other hand, benefitted from the high pressure over New Mexico, as the position created southwesterly airflow that brought copious moisture into the state. The southern and eastern counties received average or above-average precipitation (see page 12). Even western Arizona, the driest area in the state, had a very active monsoon, with some intense storms. The vigorous monsoon helped compensate for precipitation deficits seen in much of Mohave County in the northeast and western Pima County in the south.

The last 30 days were a tale of two states. While Arizona received more than 200 percent of average rainfall over large parts of Arizona, reducing precipitation deficits from the dry winter and spring, New Mexico was relatively dry (Figures 2c–d). In Arizona, only a few isolated areas received below-average rainfall.  New Mexico, on the other hand, only enjoyed rainfall over the higher elevations in the north and along the western border. The far northeastern counties received less than 50 percent of their average for this time of year.