Kirkwood, Missouri has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.9 °C (low) to 19.3 °C (high). Annual precipitation averages 1143.2 Millimeters. Kirkwood 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 | -4.2 °C | 5.1 °C | 71.37 mm |
| February | -2.4 °C | 7.9 °C | 63.5 mm |
| March | 2.3 °C | 13.7 °C | 92.71 mm |
| April | 8.3 °C | 20.1 °C | 120.14 mm |
| May | 14.2 °C | 24.9 °C | 136.65 mm |
| June | 19.2 °C | 29.7 °C | 118.36 mm |
| July | 21.4 °C | 31.6 °C | 105.41 mm |
| August | 20.2 °C | 30.9 °C | 94.74 mm |
| September | 15.8 °C | 27.3 °C | 85.6 mm |
| October | 9.8 °C | 20.8 °C | 89.66 mm |
| November | 3.2 °C | 12.9 °C | 94.74 mm |
| December | -1.4 °C | 7.2 °C | 70.36 mm |
| Annual | 8.9 °C | 19.3 °C | 1143.24 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 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |