Glenrock, Wyoming has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.3 °F (low) to 60.6 °F (high). Annual precipitation averages 13.4 Inches. Glenrock is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 15.9 °F | 38.0 °F | 0.4 in. |
| February | 17.0 °F | 39.8 °F | 0.67 in. |
| March | 24.2 °F | 49.9 °F | 0.9 in. |
| April | 30.6 °F | 56.7 °F | 1.91 in. |
| May | 39.7 °F | 66.3 °F | 2.4 in. |
| June | 48.3 °F | 78.8 °F | 1.84 in. |
| July | 55.5 °F | 88.6 °F | 0.99 in. |
| August | 53.5 °F | 86.5 °F | 1.01 in. |
| September | 43.6 °F | 76.1 °F | 1.03 in. |
| October | 32.3 °F | 60.6 °F | 1.2 in. |
| November | 23.0 °F | 47.3 °F | 0.6 in. |
| December | 16.4 °F | 38.0 °F | 0.42 in. |
| Annual | 33.3 °F | 60.6 °F | 13.37 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 | Extreme Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |