The year 2019 ended up being only the 28th warmest year recorded in the history of central Arizona (Phoenix), and the 46th warmest recorded for southwest Arizona (Yuma). Compared to recent years in Arizona which have habitually fallen in the top 10 warmest ranking due to the impacts of a rapidly changing climate, 2019 was actually somewhat cooler and ended up closer to normal than the area has become accustomed to. Records for Phoenix began in 1896, first taken in downtown and since moved to Sky Harbor airport in the 1950s. Records in Yuma began in 1878.

With a weak El Nino in place, 2019 started fairly unsettled across the Southwest United States. While temperatures in January and March were near normal, a series of potent storm systems in February resulted in a period of abnormally cool weather. In fact, the first 3 months of the year combined produced the coolest Jan-Mar in Phoenix since 1998, and coolest in Yuma since 1985. Old time residents commented that the winter 2018-19 was more like winters when they were young; and temperature records indeed support this as the average Jan-Mar temperature was similar to the average prior to 1980. While an early February storm produced substantial snowfall in northern Arizona, lower elevations experienced the greatest rain and snow during a late February storm.

Lingering cooler weather and even a few storm systems continued through the spring season as the El Nino phase was very slow to deteriorate. May 2019 was significantly cooler than normal, and in fact the monthly average temperature was nearly identical to that in April. This pattern actually held into the early summer and resulted in a lack of thunderstorm activity during the first part of the monsoon. Storm days increased during the second half of the monsoon with the greatest impacts occurring during the month of September. In fact, the first day of September provided some activity across SE California and western AZ. The most notable and memorable storm system swept into the Phoenix metro on September 23rd. In addition to localized heavy rainfall, a brief, weak tornado touched down north of the city. Overall, monsoon 2019 turned out to be one of the hotter and drier monsoon seasons on record.

The monsoon thunderstorm activity ended quicker than it began with dry weather and renewed drought concerns heading through the autumn season. However, an abrupt pattern shift towards the middle of November provided the mechanism to bring several strong storm systems into the Southwest United States. The most significant storm, and one that will probably be remembered for years to come arrived over the Thanksgiving holiday and yielded numerous brief tornadoes across the east parts of the Phoenix metro. The mild, wet pattern continued into December with several storm systems producing more rain and snow for the region, and temporarily easing drought concerns.