Hazelwood, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 8.8 °C (low) to 19.1 °C (high). Annual precipitation averages 1091.9 Millimeters. Hazelwood 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 Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.3 °C | 4.4 °C | 67.06 mm |
| February | -2.7 °C | 7.7 °C | 55.12 mm |
| March | 2.3 °C | 13.3 °C | 87.88 mm |
| April | 8.3 °C | 19.7 °C | 123.95 mm |
| May | 14.3 °C | 24.7 °C | 128.52 mm |
| June | 19.4 °C | 29.5 °C | 117.6 mm |
| July | 21.5 °C | 31.4 °C | 99.57 mm |
| August | 20.4 °C | 30.8 °C | 90.42 mm |
| September | 15.8 °C | 27 °C | 80.52 mm |
| October | 9.4 °C | 20.7 °C | 83.06 mm |
| November | 3 °C | 12.9 °C | 89.15 mm |
| December | -1.8 °C | 7 °C | 69.09 mm |
| Annual | 8.8 °C | 19.1 °C | 1091.94 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| 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 | Dfa - Humid Continental Hot Summers With Year Around Precipitation |