The Five Seasons of the Sonoran Desert

Seasons are a way of dividing up the year based on changes in weather and daylight hours. Winter, spring, summer, and fall – the traditional four – are familiar to most people. However, while traveling in southern Arizona recently, I had the opportunity to learn about the unusual fifth season of the Sonoran Desert.

The Sonoran desert, covering a large part of the southwestern US and Northern Mexico, basically divides its summer into two parts. “Fore-summer”, occurring in May and June, is very hot and very dry. “Summer monsoon season” follows it from July to mid-September and brings the region soaking rains.  It is considered the major growing season.

Surprisingly lush by desert standards, the Sonoran Desert is one of the wettest deserts in North America.  This is due to the fact that winter there is considered a second rainy season. While the precipitation that falls between December and January is generally not as intense as during the monsoon months, it tends to be more widespread. Overall, the region averages between 3 and 12 inches of rain a year. Spring and Fall are generally warm and dry.