Grover, Colorado has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 0.3 °C (low) to 16.9 °C (high). Annual precipitation averages 368.8 Millimeters. Grover is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.9 °C | 4.8 °C | 6.6 mm |
| February | -9.3 °C | 5.9 °C | 8.13 mm |
| March | -5.2 °C | 11.3 °C | 18.54 mm |
| April | -1.2 °C | 15.2 °C | 38.61 mm |
| May | 4.2 °C | 20.3 °C | 64.01 mm |
| June | 9.6 °C | 26.9 °C | 55.63 mm |
| July | 13 °C | 31.1 °C | 50.8 mm |
| August | 11.7 °C | 29.8 °C | 45.97 mm |
| September | 6.9 °C | 25.2 °C | 34.54 mm |
| October | 0.1 °C | 17.2 °C | 26.42 mm |
| November | -5.8 °C | 9.9 °C | 11.43 mm |
| December | -10.1 °C | 4.9 °C | 8.13 mm |
| Annual | 0.3 °C | 16.9 °C | 368.81 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |