Jamestown, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 7.2 °C (low) to 18.4 °C (high). Annual precipitation averages 1092.2 Millimeters. Jamestown 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 | -6.1 °C | 3.9 °C | 54.36 mm |
| February | -3.9 °C | 6.9 °C | 55.37 mm |
| March | 1.1 °C | 12.9 °C | 77.72 mm |
| April | 6.7 °C | 18.9 °C | 122.43 mm |
| May | 12.6 °C | 23.8 °C | 128.52 mm |
| June | 17.7 °C | 28.6 °C | 114.55 mm |
| July | 19.9 °C | 30.9 °C | 113.54 mm |
| August | 18.7 °C | 30.6 °C | 96.77 mm |
| September | 14.1 °C | 26.4 °C | 105.41 mm |
| October | 7.6 °C | 19.8 °C | 90.42 mm |
| November | 1.5 °C | 12.3 °C | 75.69 mm |
| December | -3.6 °C | 5.9 °C | 57.4 mm |
| Annual | 7.2 °C | 18.4 °C | 1092.18 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 100-125 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 |