South Hill, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 5.7 °C (low) to 15.6 °C (high). Annual precipitation averages 1136.1 Millimeters. South Hill is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.2 °C | 7.9 °C | 155.45 mm |
| February | 1.1 °C | 9.3 °C | 104.39 mm |
| March | 2.4 °C | 11.8 °C | 119.63 mm |
| April | 4.1 °C | 14.4 °C | 97.28 mm |
| May | 7.2 °C | 18.3 °C | 72.14 mm |
| June | 9.7 °C | 20.8 °C | 56.13 mm |
| July | 11.6 °C | 24.7 °C | 24.13 mm |
| August | 11.7 °C | 25.1 °C | 25.65 mm |
| September | 9.4 °C | 21.7 °C | 41.66 mm |
| October | 5.9 °C | 15.6 °C | 110.24 mm |
| November | 2.9 °C | 10.6 °C | 171.45 mm |
| December | 1 °C | 7.5 °C | 157.99 mm |
| Annual | 5.7 °C | 15.6 °C | 1136.14 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |