Arizona Climate

Residents who moved to this city from temperate climates often complain about the lack of seasons. Actually Arizona Upland has five seasons, which, though more subtle than the traditional temperate four, are distinct if one learns what to look for:

Don't think of the Sahara. The Arizona desert is quite different.

Summer monsoon or summer rainy season (early July to mid- September):

The year traditionally begins with the most dramatic weather event of the region - the often abrupt arrival of the summer rains. A tropical air mass adds humidity and moderates June's extreme temperatures; frequent thunderstorms; main growing season for many of the larger shrubs and trees. (Monsoon is an Arabic word for a wind that changes directions seasonally. Be aware that it does not refer to rain or storms in any way. The word is often misused, even by some weather forecasters.)

Autumn (October & November):

Warm temperatures; low humidity; little rain; few species in flower, but beginning of growing season for winter annuals in the rare years with enough rain. Autumn and late summer occasionally receive heavy rains from the remains of Pacific hurricanes (tropical storms) This image is of the Baboquivari Mountains and the Avra Valley from the Desert Museum.

Winter (December & January & February):

Mostly sunny, mild days, with intermittent storms with wind, rain, and cool to cold temperatures; February often warm and dry, more spring-like. At times you can even see a rare snowfall in the Tucson Mountains.

Spring (From early to late February through April):

Mild temperatures; little rain; often windy; main flowering season for annuals, shrubs and trees; winter annuals may bloom in February in warm, wet years.

Foresummer drought. (May & June):

High temperatures; very low humidity; no rain in most years; May is very warm and often windy; June is hot and usually calm. There is little biological activity except for the flowering and fruiting of saguaro, foothill palo verdes (as seen at left), and desert ironwood trees. Nearly every living thing is in basic survival mode until the rains arrive.