Twain, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 37.2 °F (low) to 69.8 °F (high). Annual precipitation averages 39.6 Inches. Twain is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 28.5 °F | 49.5 °F | 6.98 in. |
| February | 29.2 °F | 53.7 °F | 6.46 in. |
| March | 32.4 °F | 58.9 °F | 6.03 in. |
| April | 34.6 °F | 66.3 °F | 3.19 in. |
| May | 40.7 °F | 74.9 °F | 2.04 in. |
| June | 46.2 °F | 84.8 °F | 0.79 in. |
| July | 50.6 °F | 93.0 °F | 0.1 in. |
| August | 47.7 °F | 92.5 °F | 0.12 in. |
| September | 41.8 °F | 86.4 °F | 0.36 in. |
| October | 35.0 °F | 73.2 °F | 1.98 in. |
| November | 31.6 °F | 57.0 °F | 3.84 in. |
| December | 27.9 °F | 47.4 °F | 7.71 in. |
| Annual | 37.2 °F | 69.8 °F | 39.6 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 8a : 10°F to 15°F |
| Plant Hardiness Zone - 2012 | Zone 8a : 10°F to 15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |