Jamestown, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.2 °F (low) to 61.3 °F (high). Annual precipitation averages 43.6 Inches. Jamestown is located in USDA Plant Hardiness Zone 6a. 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 | 18.8 °F | 34.5 °F | 2.93 in. |
| February | 21.3 °F | 38.4 °F | 2.45 in. |
| March | 30.6 °F | 49.3 °F | 3.21 in. |
| April | 41.2 °F | 61.9 °F | 4.47 in. |
| May | 52.5 °F | 72.5 °F | 4.69 in. |
| June | 60.9 °F | 80.5 °F | 5.16 in. |
| July | 64.0 °F | 83.6 °F | 4.48 in. |
| August | 61.9 °F | 82.3 °F | 3.34 in. |
| September | 54.3 °F | 77.3 °F | 3.31 in. |
| October | 43.2 °F | 65.2 °F | 3.26 in. |
| November | 33.0 °F | 50.6 °F | 3.4 in. |
| December | 24.1 °F | 39.1 °F | 2.9 in. |
| Annual | 42.2 °F | 61.3 °F | 43.6 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |