San Tan Valley, Arizona has a Hot Semi-Arid Climate climate (Köppen classification: BSh). Average annual temperatures range from 14.6 °C (low) to 29.8 °C (high). Annual precipitation averages 222.8 Millimeters. San Tan Valley is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Feb. 1 - Feb. 10 through the first frost around Dec. 11 - Dec. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 5.2 °C | 19.3 °C | 33.02 mm |
| February | 6.4 °C | 21.1 °C | 26.42 mm |
| March | 8.8 °C | 24.7 °C | 29.72 mm |
| April | 11.9 °C | 28.7 °C | 8.38 mm |
| May | 16.9 °C | 33.9 °C | 4.57 mm |
| June | 21.9 °C | 39.1 °C | 1.27 mm |
| July | 25.7 °C | 40.1 °C | 19.56 mm |
| August | 25.4 °C | 39.4 °C | 24.89 mm |
| September | 22.3 °C | 37.1 °C | 15.49 mm |
| October | 15.6 °C | 31.3 °C | 10.92 mm |
| November | 9.3 °C | 24.4 °C | 15.75 mm |
| December | 5.2 °C | 18.7 °C | 32.77 mm |
| Annual | 14.6 °C | 29.8 °C | 222.76 mm |
| Average First Frost Date | Dec. 11 - Dec. 20 |
| Average Last Frost Date | Feb. 1 - Feb. 10 |
| Average Days With Frost | 10-20 Days |
| Plant Hardiness Zone | Zone 9b : -3.9°C to -1.1°C |
| Plant Hardiness Zone - 2012 | Zone 9b : -3.9°C to -1.1°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSh - Hot Semi-Arid Climate |