Elma, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 5.7 °C (low) to 16.6 °C (high). Annual precipitation averages 1775.5 Millimeters. 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 | 2.1 °C | 8.7 °C | 274.57 mm |
| February | 1.7 °C | 10.3 °C | 176.53 mm |
| March | 2.6 °C | 12.5 °C | 202.44 mm |
| April | 4.1 °C | 15.8 °C | 135.13 mm |
| May | 7 °C | 19.6 °C | 76.71 mm |
| June | 9.2 °C | 21.7 °C | 57.91 mm |
| July | 11.2 °C | 24.9 °C | 20.07 mm |
| August | 11.1 °C | 26.1 °C | 34.54 mm |
| September | 9.2 °C | 23.3 °C | 64.26 mm |
| October | 5.9 °C | 17.2 °C | 171.45 mm |
| November | 3.1 °C | 11.1 °C | 284.23 mm |
| December | 1.7 °C | 8.1 °C | 277.62 mm |
| Annual | 5.7 °C | 16.6 °C | 1775.46 mm |
| 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 : -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 |