Etna, Wyoming has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -2.9 °C (low) to 12.3 °C (high). Annual precipitation averages 533.2 Millimeters. 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 | -13.2 °C | -1.7 °C | 65.28 mm |
| February | -12.3 °C | 0.2 °C | 51.31 mm |
| March | -7.7 °C | 5.4 °C | 41.91 mm |
| April | -2.9 °C | 10.4 °C | 48.77 mm |
| May | 1.6 °C | 16.8 °C | 62.23 mm |
| June | 4.6 °C | 22.2 °C | 45.21 mm |
| July | 7.4 °C | 28 °C | 25.65 mm |
| August | 6.8 °C | 27.4 °C | 31.24 mm |
| September | 2.4 °C | 22.2 °C | 38.61 mm |
| October | -1.8 °C | 13.8 °C | 39.88 mm |
| November | -7.1 °C | 4.9 °C | 44.2 mm |
| December | -12.2 °C | -1.8 °C | 38.86 mm |
| Annual | -2.9 °C | 12.3 °C | 533.15 mm |
| 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 : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |