Rowan, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 36.1 °F (low) to 56.3 °F (high). Annual precipitation averages 35.8 Inches. Rowan 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 | 7.9 °F | 24.9 °F | 0.85 in. |
| February | 11.7 °F | 29.6 °F | 1.0 in. |
| March | 23.7 °F | 42.4 °F | 2.03 in. |
| April | 35.0 °F | 57.4 °F | 3.84 in. |
| May | 48.1 °F | 69.4 °F | 5.06 in. |
| June | 58.7 °F | 79.6 °F | 5.7 in. |
| July | 61.8 °F | 82.3 °F | 4.42 in. |
| August | 58.7 °F | 80.1 °F | 4.2 in. |
| September | 49.7 °F | 74.4 °F | 3.21 in. |
| October | 37.4 °F | 60.9 °F | 2.43 in. |
| November | 25.5 °F | 44.3 °F | 1.72 in. |
| December | 14.4 °F | 30.6 °F | 1.31 in. |
| Annual | 36.1 °F | 56.3 °F | 35.77 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 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 |