Evanston, Wyoming has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 27.6 °F (low) to 55.3 °F (high). Annual precipitation averages 12.2 Inches. Evanston 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 Sep.1 - Sep. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 10.6 °F | 32.6 °F | 0.73 in. |
| February | 11.6 °F | 34.9 °F | 0.64 in. |
| March | 19.7 °F | 43.9 °F | 0.72 in. |
| April | 25.9 °F | 51.5 °F | 1.16 in. |
| May | 33.4 °F | 61.3 °F | 1.69 in. |
| June | 40.0 °F | 72.4 °F | 1.22 in. |
| July | 47.6 °F | 82.2 °F | 0.72 in. |
| August | 46.6 °F | 80.5 °F | 1.04 in. |
| September | 38.4 °F | 71.2 °F | 1.27 in. |
| October | 28.1 °F | 57.7 °F | 1.22 in. |
| November | 18.6 °F | 43.2 °F | 0.97 in. |
| December | 10.1 °F | 32.7 °F | 0.83 in. |
| Annual | 27.6 °F | 55.3 °F | 12.21 in. |
| Average First Frost Date | Sep.1 - Sep. 10 |
| 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 5a : -20°F to -15°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |