Atascadero, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 43.7 °F (low) to 73.9 °F (high). Annual precipitation averages 22.4 Inches. Atascadero is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Feb. 11 - Feb. 20 through the first frost around Dec. 11 - Dec. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 37.0 °F | 61.9 °F | 5.02 in. |
| February | 38.2 °F | 63.4 °F | 4.85 in. |
| March | 40.2 °F | 66.5 °F | 3.98 in. |
| April | 41.2 °F | 69.8 °F | 1.33 in. |
| May | 44.7 °F | 74.2 °F | 0.49 in. |
| June | 48.8 °F | 82.2 °F | 0.09 in. |
| July | 52.6 °F | 86.2 °F | 0.04 in. |
| August | 52.0 °F | 87.7 °F | 0.02 in. |
| September | 49.4 °F | 85.3 °F | 0.09 in. |
| October | 45.2 °F | 78.4 °F | 0.98 in. |
| November | 39.7 °F | 69.2 °F | 1.74 in. |
| December | 35.9 °F | 61.5 °F | 3.73 in. |
| Annual | 43.7 °F | 73.9 °F | 22.36 in. |
| Average First Frost Date | Dec. 11 - Dec. 20 |
| Average Last Frost Date | Feb. 11 - Feb. 20 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9a : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 9a : 20°F to 25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |