San Jacinto, California has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 9.4 °C (low) to 26.8 °C (high). Annual precipitation averages 312.9 Millimeters. San Jacinto is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Feb. 11 - Feb. 20 through the first frost around Dec. 1 - Dec. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 4 °C | 19.3 °C | 66.29 mm |
| February | 4.4 °C | 19.3 °C | 74.17 mm |
| March | 6 °C | 21.4 °C | 47.75 mm |
| April | 7.6 °C | 24.3 °C | 19.81 mm |
| May | 10.6 °C | 27.7 °C | 10.16 mm |
| June | 12.8 °C | 32.1 °C | 1.27 mm |
| July | 16.1 °C | 36 °C | 4.32 mm |
| August | 16.4 °C | 36.7 °C | 2.79 mm |
| September | 14.6 °C | 34.2 °C | 6.1 mm |
| October | 10.6 °C | 28.8 °C | 15.75 mm |
| November | 6.6 °C | 23.3 °C | 19.56 mm |
| December | 3.3 °C | 18.9 °C | 44.96 mm |
| Annual | 9.4 °C | 26.8 °C | 312.93 mm |
| Average First Frost Date | Dec. 1 - Dec. 10 |
| Average Last Frost Date | Feb. 11 - Feb. 20 |
| 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 | Abnormally Dry |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |