Granger, Wyoming has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 27.5 °F (low) to 57.6 °F (high). Annual precipitation averages 8.6 Inches. Granger is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 6.5 °F | 31.9 °F | 0.44 in. |
| February | 9.6 °F | 35.5 °F | 0.41 in. |
| March | 20.0 °F | 46.0 °F | 0.62 in. |
| April | 27.2 °F | 55.5 °F | 0.92 in. |
| May | 35.5 °F | 65.4 °F | 1.45 in. |
| June | 42.9 °F | 76.8 °F | 0.93 in. |
| July | 49.3 °F | 85.6 °F | 0.53 in. |
| August | 47.1 °F | 83.8 °F | 0.67 in. |
| September | 38.5 °F | 74.1 °F | 0.92 in. |
| October | 27.9 °F | 59.6 °F | 0.85 in. |
| November | 17.9 °F | 44.3 °F | 0.47 in. |
| December | 8.1 °F | 33.0 °F | 0.39 in. |
| Annual | 27.5 °F | 57.6 °F | 8.6 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |