Blue Grass, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.6 °C (low) to 15.2 °C (high). Annual precipitation averages 964.4 Millimeters. Blue Grass is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.2 °C | -1.2 °C | 37.08 mm |
| February | -8.3 °C | 1.2 °C | 43.94 mm |
| March | -2.3 °C | 8.4 °C | 62.74 mm |
| April | 3.9 °C | 15.8 °C | 94.23 mm |
| May | 10.6 °C | 21.9 °C | 123.44 mm |
| June | 16.1 °C | 27.1 °C | 125.22 mm |
| July | 18.1 °C | 28.8 °C | 106.43 mm |
| August | 16.8 °C | 27.8 °C | 101.85 mm |
| September | 12.3 °C | 24.6 °C | 90.42 mm |
| October | 5.7 °C | 17.3 °C | 72.9 mm |
| November | -1 °C | 9.1 °C | 57.15 mm |
| December | -6.9 °C | 1.7 °C | 49.02 mm |
| Annual | 4.6 °C | 15.2 °C | 964.42 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |