Blue Grass, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.2 °F (low) to 59.4 °F (high). Annual precipitation averages 38 Inches. 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 | 13.6 °F | 29.8 °F | 1.46 in. |
| February | 17.0 °F | 34.2 °F | 1.73 in. |
| March | 27.9 °F | 47.2 °F | 2.47 in. |
| April | 39.1 °F | 60.4 °F | 3.71 in. |
| May | 51.0 °F | 71.4 °F | 4.86 in. |
| June | 60.9 °F | 80.7 °F | 4.93 in. |
| July | 64.5 °F | 83.8 °F | 4.19 in. |
| August | 62.3 °F | 82.0 °F | 4.01 in. |
| September | 54.1 °F | 76.2 °F | 3.56 in. |
| October | 42.2 °F | 63.2 °F | 2.87 in. |
| November | 30.2 °F | 48.3 °F | 2.25 in. |
| December | 19.6 °F | 35.1 °F | 1.93 in. |
| Annual | 40.2 °F | 59.4 °F | 37.97 in. |
| 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 : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |