Keystone, Nebraska has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 36.5 °F (low) to 63.5 °F (high). Annual precipitation averages 19.3 Inches. Keystone is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 15.6 °F | 39.4 °F | 0.33 in. |
| February | 17.7 °F | 42.1 °F | 0.52 in. |
| March | 24.9 °F | 53.2 °F | 0.99 in. |
| April | 33.7 °F | 61.4 °F | 2.16 in. |
| May | 44.7 °F | 71.1 °F | 3.45 in. |
| June | 55.6 °F | 83.0 °F | 3.27 in. |
| July | 61.0 °F | 89.1 °F | 2.85 in. |
| August | 59.0 °F | 86.9 °F | 2.13 in. |
| September | 49.6 °F | 79.0 °F | 1.49 in. |
| October | 36.0 °F | 65.0 °F | 1.29 in. |
| November | 24.5 °F | 51.3 °F | 0.5 in. |
| December | 16.2 °F | 40.2 °F | 0.34 in. |
| Annual | 36.5 °F | 63.5 °F | 19.32 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |