Grover, Wyoming has a Subarctic With Cool Summers And Year Around Rainfall climate (Köppen classification: Dfc). Average annual temperatures range from -3.9 °C (low) to 11.9 °C (high). Annual precipitation averages 531.6 Millimeters. Grover is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around Jun. 1 - Jun. 10 through the first frost around Aug. 11 - Aug. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.3 °C | -2.1 °C | 48.51 mm |
| February | -13.3 °C | 0 °C | 43.43 mm |
| March | -8.6 °C | 5.2 °C | 44.2 mm |
| April | -3.7 °C | 10 °C | 51.05 mm |
| May | 0.7 °C | 16.1 °C | 68.07 mm |
| June | 3.6 °C | 21.4 °C | 46.48 mm |
| July | 6.6 °C | 27.1 °C | 25.15 mm |
| August | 5.8 °C | 26.8 °C | 29.72 mm |
| September | 1.5 °C | 21.5 °C | 38.1 mm |
| October | -2.9 °C | 13.4 °C | 45.21 mm |
| November | -8.1 °C | 4.8 °C | 42.67 mm |
| December | -13.6 °C | -1.8 °C | 49.02 mm |
| Annual | -3.9 °C | 11.9 °C | 531.61 mm |
| Average First Frost Date | Aug. 11 - Aug. 20 |
| Average Last Frost Date | Jun. 1 - Jun. 10 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Dfc - Subarctic With Cool Summers And Year Around Rainfall |