Etna, Wyoming has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 26.8 °F (low) to 54.2 °F (high). Annual precipitation averages 21 Inches. Etna is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Aug. 21 - Aug. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 8.3 °F | 29.0 °F | 2.57 in. |
| February | 9.9 °F | 32.4 °F | 2.02 in. |
| March | 18.1 °F | 41.7 °F | 1.65 in. |
| April | 26.8 °F | 50.8 °F | 1.92 in. |
| May | 34.8 °F | 62.3 °F | 2.45 in. |
| June | 40.2 °F | 72.0 °F | 1.78 in. |
| July | 45.4 °F | 82.4 °F | 1.01 in. |
| August | 44.2 °F | 81.4 °F | 1.23 in. |
| September | 36.4 °F | 72.0 °F | 1.52 in. |
| October | 28.8 °F | 56.8 °F | 1.57 in. |
| November | 19.2 °F | 40.8 °F | 1.74 in. |
| December | 10.0 °F | 28.8 °F | 1.53 in. |
| Annual | 26.8 °F | 54.2 °F | 20.99 in. |
| Average First Frost Date | Aug. 21 - Aug. 31 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |