Montpelier, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.4 °F (low) to 60.6 °F (high). Annual precipitation averages 37.8 Inches. Montpelier is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 14.8 °F | 30.8 °F | 1.44 in. |
| February | 18.3 °F | 35.3 °F | 1.71 in. |
| March | 29.1 °F | 48.2 °F | 2.44 in. |
| April | 40.3 °F | 61.7 °F | 3.69 in. |
| May | 52.2 °F | 72.7 °F | 4.87 in. |
| June | 62.1 °F | 82.0 °F | 4.96 in. |
| July | 65.7 °F | 85.2 °F | 4.15 in. |
| August | 63.4 °F | 83.3 °F | 4.0 in. |
| September | 55.3 °F | 77.4 °F | 3.57 in. |
| October | 43.3 °F | 64.5 °F | 2.86 in. |
| November | 31.4 °F | 49.3 °F | 2.24 in. |
| December | 20.9 °F | 36.2 °F | 1.91 in. |
| Annual | 41.4 °F | 60.6 °F | 37.84 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°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 |