Manly, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 35.6 °F (low) to 55.1 °F (high). Annual precipitation averages 36 Inches. Manly is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 6.7 °F | 23.6 °F | 0.96 in. |
| February | 10.7 °F | 28.1 °F | 1.07 in. |
| March | 22.9 °F | 40.6 °F | 1.96 in. |
| April | 34.9 °F | 56.1 °F | 3.86 in. |
| May | 47.3 °F | 68.4 °F | 5.13 in. |
| June | 58.1 °F | 78.3 °F | 5.43 in. |
| July | 61.5 °F | 81.4 °F | 4.61 in. |
| August | 58.7 °F | 79.1 °F | 4.0 in. |
| September | 50.0 °F | 73.0 °F | 3.41 in. |
| October | 37.5 °F | 59.5 °F | 2.58 in. |
| November | 25.3 °F | 43.1 °F | 1.71 in. |
| December | 13.8 °F | 29.4 °F | 1.32 in. |
| Annual | 35.6 °F | 55.1 °F | 36.04 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |