Carter Lake, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.1 °F (low) to 61.8 °F (high). Annual precipitation averages 32.9 Inches. Carter Lake is located in USDA Plant Hardiness Zone 6a. 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 | 13.2 °F | 32.3 °F | 0.82 in. |
| February | 17.0 °F | 37.4 °F | 1.03 in. |
| March | 27.9 °F | 50.3 °F | 1.79 in. |
| April | 38.9 °F | 63.2 °F | 3.42 in. |
| May | 51.3 °F | 73.3 °F | 4.98 in. |
| June | 62.0 °F | 83.3 °F | 4.71 in. |
| July | 66.2 °F | 86.8 °F | 3.57 in. |
| August | 63.5 °F | 84.9 °F | 4.09 in. |
| September | 53.9 °F | 78.5 °F | 3.12 in. |
| October | 41.1 °F | 65.5 °F | 2.59 in. |
| November | 28.4 °F | 49.7 °F | 1.48 in. |
| December | 18.3 °F | 36.8 °F | 1.34 in. |
| Annual | 40.1 °F | 61.8 °F | 32.94 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 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 |