Herlong, California has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 2.7 °C (low) to 18.9 °C (high). Annual precipitation averages 246.4 Millimeters. Herlong is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.8 °C | 6.6 °C | 43.18 mm |
| February | -3.1 °C | 9.3 °C | 30.73 mm |
| March | -0.8 °C | 13.4 °C | 28.19 mm |
| April | 1.2 °C | 16.9 °C | 14.99 mm |
| May | 5.2 °C | 21.9 °C | 20.57 mm |
| June | 8.4 °C | 27.7 °C | 13.72 mm |
| July | 12.4 °C | 32.8 °C | 6.1 mm |
| August | 11.4 °C | 32.1 °C | 4.06 mm |
| September | 7.8 °C | 27.7 °C | 5.59 mm |
| October | 2.3 °C | 20.3 °C | 16.26 mm |
| November | -2.3 °C | 11.8 °C | 22.86 mm |
| December | -5.1 °C | 6.2 °C | 40.13 mm |
| Annual | 2.7 °C | 18.9 °C | 246.38 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |