Swaledale, 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 13.3 °C (high). Annual precipitation averages 918.2 Millimeters. Swaledale 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 | -13.6 °C | -4.1 °C | 23.37 mm |
| February | -11.3 °C | -1.6 °C | 27.18 mm |
| March | -4.6 °C | 5.4 °C | 51.05 mm |
| April | 1.8 °C | 13.9 °C | 99.06 mm |
| May | 8.8 °C | 20.7 °C | 130.56 mm |
| June | 14.7 °C | 26.3 °C | 142.75 mm |
| July | 16.6 °C | 27.9 °C | 114.81 mm |
| August | 15 °C | 26.7 °C | 102.62 mm |
| September | 10.1 °C | 23.3 °C | 84.33 mm |
| October | 3.2 °C | 15.9 °C | 64.26 mm |
| November | -3.6 °C | 6.6 °C | 43.94 mm |
| December | -9.8 °C | -0.9 °C | 34.29 mm |
| Annual | 2.3 °C | 13.3 °C | 918.22 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 | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |