Brewster, Kansas has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 37 °F (low) to 66 °F (high). Annual precipitation averages 19.5 Inches. Brewster is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.0 °F | 42.4 °F | 0.32 in. |
| February | 17.9 °F | 45.3 °F | 0.49 in. |
| March | 25.5 °F | 55.7 °F | 0.86 in. |
| April | 33.9 °F | 64.3 °F | 1.67 in. |
| May | 45.2 °F | 73.9 °F | 2.72 in. |
| June | 56.0 °F | 85.8 °F | 2.87 in. |
| July | 61.5 °F | 91.3 °F | 3.35 in. |
| August | 59.5 °F | 88.5 °F | 3.05 in. |
| September | 50.2 °F | 80.7 °F | 1.54 in. |
| October | 36.6 °F | 67.3 °F | 1.55 in. |
| November | 25.1 °F | 53.4 °F | 0.66 in. |
| December | 17.1 °F | 43.3 °F | 0.41 in. |
| Annual | 37 °F | 66 °F | 19.49 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |