Rainbow, California has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 11.3 °C (low) to 24.9 °C (high). Annual precipitation averages 412.3 Millimeters. Rainbow is located in USDA Plant Hardiness Zone 10a. The growing season typically runs from the last frost around Feb. 1 - Feb. 10 through the first frost around Dec. 21 - Dec. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 7.6 °C | 19.7 °C | 71.88 mm |
| February | 7.7 °C | 19.5 °C | 106.93 mm |
| March | 8.2 °C | 20.3 °C | 61.47 mm |
| April | 9.2 °C | 22.4 °C | 27.94 mm |
| May | 11.4 °C | 24.6 °C | 14.99 mm |
| June | 13.2 °C | 27.3 °C | 5.08 mm |
| July | 15.6 °C | 31.2 °C | 3.56 mm |
| August | 16.3 °C | 32.2 °C | 1.78 mm |
| September | 15.7 °C | 31.4 °C | 3.3 mm |
| October | 13.2 °C | 28.2 °C | 16.26 mm |
| November | 10 °C | 23.2 °C | 28.7 mm |
| December | 7.2 °C | 19.3 °C | 70.36 mm |
| Annual | 11.3 °C | 24.9 °C | 412.25 mm |
| Average First Frost Date | Dec. 21 - Dec. 31 |
| Average Last Frost Date | Feb. 1 - Feb. 10 |
| Average Days With Frost | 10-20 Days |
| Plant Hardiness Zone | Zone 10a : -1.1°C to 1.7°C |
| Plant Hardiness Zone - 2012 | Zone 10a : -1.1°C to 1.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |