Elma, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 42.3 °F (low) to 61.9 °F (high). Annual precipitation averages 69.9 Inches. Elma 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 35.8 °F | 47.7 °F | 10.81 in. |
| February | 35.0 °F | 50.5 °F | 6.95 in. |
| March | 36.7 °F | 54.5 °F | 7.97 in. |
| April | 39.4 °F | 60.4 °F | 5.32 in. |
| May | 44.6 °F | 67.2 °F | 3.02 in. |
| June | 48.6 °F | 71.0 °F | 2.28 in. |
| July | 52.1 °F | 76.9 °F | 0.79 in. |
| August | 52.0 °F | 78.9 °F | 1.36 in. |
| September | 48.5 °F | 73.9 °F | 2.53 in. |
| October | 42.7 °F | 63.0 °F | 6.75 in. |
| November | 37.6 °F | 52.0 °F | 11.19 in. |
| December | 35.0 °F | 46.6 °F | 10.93 in. |
| Annual | 42.3 °F | 61.9 °F | 69.9 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| 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 |