Atlantic, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.6 °C (low) to 15.6 °C (high). Annual precipitation averages 884.4 Millimeters. Atlantic is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.3 °C | -0.9 °C | 21.84 mm |
| February | -9.1 °C | 1.8 °C | 30.23 mm |
| March | -2.9 °C | 9.2 °C | 48.51 mm |
| April | 3 °C | 16.4 °C | 91.69 mm |
| May | 9.9 °C | 22.1 °C | 137.41 mm |
| June | 15.7 °C | 27.4 °C | 116.33 mm |
| July | 17.7 °C | 29.3 °C | 99.06 mm |
| August | 16.2 °C | 28.3 °C | 103.38 mm |
| September | 11.1 °C | 24.9 °C | 85.6 mm |
| October | 4.3 °C | 17.8 °C | 72.64 mm |
| November | -2.7 °C | 9 °C | 42.42 mm |
| December | -8.2 °C | 1.8 °C | 35.31 mm |
| Annual | 3.6 °C | 15.6 °C | 884.42 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |