South Bend, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 43.5 °F (low) to 59.7 °F (high). Annual precipitation averages 83.3 Inches. South Bend is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 37.3 °F | 48.6 °F | 12.98 in. |
| February | 36.4 °F | 50.8 °F | 8.17 in. |
| March | 38.0 °F | 53.4 °F | 9.41 in. |
| April | 40.5 °F | 58.0 °F | 6.83 in. |
| May | 45.3 °F | 63.3 °F | 3.66 in. |
| June | 49.4 °F | 66.8 °F | 2.81 in. |
| July | 52.7 °F | 70.9 °F | 1.11 in. |
| August | 52.6 °F | 72.3 °F | 1.5 in. |
| September | 49.4 °F | 70.0 °F | 2.97 in. |
| October | 44.1 °F | 61.5 °F | 7.99 in. |
| November | 39.3 °F | 53.0 °F | 12.8 in. |
| December | 36.6 °F | 47.9 °F | 13.04 in. |
| Annual | 43.5 °F | 59.7 °F | 83.27 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8b : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |