Arcata, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 7.9 °C (low) to 16 °C (high). Annual precipitation averages 1167.6 Millimeters. Arcata 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 Jan. 1 - Jan. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 5.3 °C | 13.1 °C | 196.34 mm |
| February | 5.4 °C | 13.4 °C | 154.94 mm |
| March | 5.8 °C | 13.7 °C | 173.48 mm |
| April | 6.7 °C | 14.8 °C | 102.11 mm |
| May | 8.5 °C | 16.2 °C | 43.18 mm |
| June | 9.9 °C | 17.7 °C | 24.13 mm |
| July | 11.3 °C | 18.3 °C | 5.84 mm |
| August | 11.6 °C | 18.9 °C | 6.1 mm |
| September | 10.2 °C | 19.4 °C | 22.35 mm |
| October | 8.2 °C | 18.4 °C | 62.23 mm |
| November | 6.6 °C | 14.7 °C | 143.51 mm |
| December | 5 °C | 12.8 °C | 233.43 mm |
| Annual | 7.9 °C | 16 °C | 1167.64 mm |
| Average First Frost Date | Jan. 1 - Jan. 10 |
| 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 | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |