Glennville, California has a Hot Semi-Arid Climate climate (Köppen classification: BSh). Average annual temperatures range from 6.8 °C (low) to 21.8 °C (high). Annual precipitation averages 502.9 Millimeters. Glennville is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.9 °C | 13.4 °C | 96.01 mm |
| February | 1.3 °C | 13.7 °C | 97.28 mm |
| March | 2.7 °C | 15.7 °C | 75.44 mm |
| April | 4.1 °C | 18.5 °C | 48.77 mm |
| May | 7.4 °C | 23.4 °C | 21.08 mm |
| June | 11.4 °C | 28.8 °C | 4.32 mm |
| July | 15.3 °C | 32.9 °C | 2.29 mm |
| August | 14.7 °C | 32.8 °C | 2.29 mm |
| September | 12.3 °C | 29.7 °C | 3.3 mm |
| October | 7.7 °C | 23.4 °C | 21.34 mm |
| November | 3.6 °C | 17 °C | 49.02 mm |
| December | 0.5 °C | 12.6 °C | 81.79 mm |
| Annual | 6.8 °C | 21.8 °C | 502.93 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | BSh - Hot Semi-Arid Climate |