Gridley, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 49.3 °F (low) to 74.7 °F (high). Annual precipitation averages 25.5 Inches. Gridley 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 | 39.0 °F | 55.6 °F | 4.75 in. |
| February | 41.5 °F | 60.8 °F | 4.18 in. |
| March | 43.8 °F | 66.2 °F | 3.73 in. |
| April | 46.6 °F | 72.2 °F | 1.74 in. |
| May | 53.2 °F | 80.7 °F | 1.38 in. |
| June | 58.8 °F | 88.3 °F | 0.35 in. |
| July | 61.8 °F | 93.6 °F | 0.01 in. |
| August | 60.0 °F | 92.4 °F | 0.04 in. |
| September | 56.3 °F | 88.3 °F | 0.37 in. |
| October | 49.7 °F | 78.5 °F | 1.15 in. |
| November | 42.5 °F | 64.5 °F | 2.57 in. |
| December | 38.5 °F | 55.5 °F | 5.19 in. |
| Annual | 49.3 °F | 74.7 °F | 25.46 in. |
| 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 : 25°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 9b : 25°F to 20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |