Weir, Kansas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.3 °C (low) to 20 °C (high). Annual precipitation averages 1181.6 Millimeters. Weir is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.4 °C | 6.4 °C | 40.39 mm |
| February | -2.4 °C | 9.2 °C | 47.24 mm |
| March | 2.3 °C | 14.7 °C | 82.55 mm |
| April | 7.6 °C | 19.9 °C | 125.22 mm |
| May | 13.4 °C | 24.6 °C | 177.29 mm |
| June | 18.5 °C | 29.5 °C | 149.86 mm |
| July | 20.8 °C | 32.1 °C | 114.3 mm |
| August | 19.7 °C | 31.9 °C | 91.95 mm |
| September | 15.1 °C | 27.6 °C | 120.9 mm |
| October | 8.4 °C | 21.4 °C | 95.76 mm |
| November | 2.4 °C | 14.3 °C | 75.44 mm |
| December | -2.4 °C | 8.2 °C | 60.71 mm |
| Annual | 8.3 °C | 20 °C | 1181.61 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |