Ryan, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.3 °C (low) to 13.8 °C (high). Annual precipitation averages 997.7 Millimeters. Ryan 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 | -12.9 °C | -3.2 °C | 30.99 mm |
| February | -10.8 °C | -0.8 °C | 32.77 mm |
| March | -4.4 °C | 6.6 °C | 53.34 mm |
| April | 1.8 °C | 14.3 °C | 99.06 mm |
| May | 8.4 °C | 20.8 °C | 116.84 mm |
| June | 14.3 °C | 26.1 °C | 152.4 mm |
| July | 16.1 °C | 27.9 °C | 116.84 mm |
| August | 14.7 °C | 26.8 °C | 118.36 mm |
| September | 9.8 °C | 23.3 °C | 99.57 mm |
| October | 3.2 °C | 15.9 °C | 77.22 mm |
| November | -3.3 °C | 7.3 °C | 58.67 mm |
| December | -9.2 °C | 0 °C | 41.66 mm |
| Annual | 2.3 °C | 13.8 °C | 997.72 mm |
| 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 : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |