Foristell, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 7.1 °C (low) to 18.6 °C (high). Annual precipitation averages 1095.5 Millimeters. Foristell is located in USDA Plant Hardiness Zone 6b. 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 | -6 °C | 3.8 °C | 61.21 mm |
| February | -4.1 °C | 7 °C | 59.44 mm |
| March | 0.7 °C | 12.7 °C | 82.3 mm |
| April | 6.8 °C | 19.5 °C | 116.33 mm |
| May | 12.5 °C | 24.2 °C | 131.32 mm |
| June | 17.7 °C | 28.8 °C | 118.62 mm |
| July | 19.8 °C | 31 °C | 105.66 mm |
| August | 18.7 °C | 30.4 °C | 92.46 mm |
| September | 14 °C | 26.6 °C | 90.42 mm |
| October | 7.3 °C | 20.2 °C | 85.85 mm |
| November | 1.4 °C | 12.7 °C | 85.85 mm |
| December | -3.4 °C | 6.2 °C | 66.04 mm |
| Annual | 7.1 °C | 18.6 °C | 1095.5 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 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |