Westboro, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.6 °C (low) to 16.9 °C (high). Annual precipitation averages 903 Millimeters. Westboro is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.2 °C | 0.8 °C | 20.32 mm |
| February | -7.8 °C | 3.7 °C | 28.7 mm |
| March | -1.9 °C | 10.9 °C | 50.55 mm |
| April | 4.1 °C | 17.4 °C | 86.61 mm |
| May | 10.9 °C | 23.2 °C | 139.7 mm |
| June | 16.7 °C | 28.2 °C | 129.79 mm |
| July | 18.7 °C | 30.3 °C | 118.11 mm |
| August | 17.2 °C | 29.4 °C | 95.76 mm |
| September | 11.9 °C | 26 °C | 82.8 mm |
| October | 5 °C | 19.1 °C | 70.1 mm |
| November | -1.8 °C | 10.3 °C | 47.24 mm |
| December | -7.2 °C | 3.3 °C | 33.27 mm |
| Annual | 4.6 °C | 16.9 °C | 902.95 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |