Tucson, in the Sonoran Desert of southern Arizona, receives only around 300 mm (about 12 inches) of rain a year, split between gentler winter Pacific storm remnants and the more dramatic summer North American Monsoon from July through September. Monsoon storms here can build explosively over the surrounding mountain ranges in the afternoon, bringing intense lightning, dust storms, and flash flooding in the desert washes that define much of the region’s low-lying terrain. Because these storms can escalate from clear skies to severe within an hour, and because so much of the surrounding desert floods quickly when it does rain, radar tracking during monsoon season is a genuinely critical tool. NWS Doppler radar KEMX (Tucson) covers the region.
Rain in Tucson by month
Tucson gets about 323 mm (12.7 in) of rain in an average year. The wettest month is July, with 83 mm (3.3 in), and the driest is May, with 4 mm (0.2 in).
| Month | Average rain | Average temperature |
|---|---|---|
| January | 25 mm (1.0 in) | 10.0 °C (50 °F) |
| February | 21 mm (0.8 in) | 11.2 °C (52 °F) |
| March | 14 mm (0.6 in) | 14.9 °C (59 °F) |
| April | 8 mm (0.3 in) | 18.5 °C (65 °F) |
| May | 4 mm (0.2 in) | 23.4 °C (74 °F) |
| June | 8 mm (0.3 in) | 29.3 °C (85 °F) |
| July | 83 mm (3.3 in) | 29.4 °C (85 °F) |
| August | 65 mm (2.5 in) | 28.7 °C (84 °F) |
| September | 40 mm (1.6 in) | 26.4 °C (80 °F) |
| October | 15 mm (0.6 in) | 20.9 °C (70 °F) |
| November | 14 mm (0.6 in) | 15.0 °C (59 °F) |
| December | 27 mm (1.1 in) | 9.7 °C (49 °F) |
Long-term monthly averages from NASA POWER (MERRA-2 satellite reanalysis). They describe the wider area around Tucson and can differ slightly from local weather-station records.
Learn more: How Does Rain Radar Work? · Open the full Rain Map