Shirley, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.2 °F (low) to 61 °F (high). Annual precipitation averages 45.1 Inches. Shirley is located in USDA Plant Hardiness Zone 6a. 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 | 18.3 °F | 34.2 °F | 3.18 in. |
| February | 20.9 °F | 38.2 °F | 2.49 in. |
| March | 29.4 °F | 48.8 °F | 3.51 in. |
| April | 39.9 °F | 61.5 °F | 4.55 in. |
| May | 51.0 °F | 72.0 °F | 4.98 in. |
| June | 60.1 °F | 80.5 °F | 5.34 in. |
| July | 62.6 °F | 83.3 °F | 4.42 in. |
| August | 60.8 °F | 82.2 °F | 3.41 in. |
| September | 53.2 °F | 77.0 °F | 3.29 in. |
| October | 42.3 °F | 64.9 °F | 3.25 in. |
| November | 32.1 °F | 50.6 °F | 3.51 in. |
| December | 23.9 °F | 38.8 °F | 3.16 in. |
| Annual | 41.2 °F | 61 °F | 45.09 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 6a : -10°F to -5°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 |