Gary, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.2 °C (low) to 15.3 °C (high). Annual precipitation averages 1025.6 Millimeters. Gary 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 | -7.2 °C | 0.4 °C | 60.2 mm |
| February | -5.7 °C | 2.4 °C | 49.78 mm |
| March | -0.9 °C | 8 °C | 60.45 mm |
| April | 4.6 °C | 14.7 °C | 91.95 mm |
| May | 10.4 °C | 20.7 °C | 109.98 mm |
| June | 15.9 °C | 26.2 °C | 113.03 mm |
| July | 18.9 °C | 28.5 °C | 109.47 mm |
| August | 18.5 °C | 27.7 °C | 103.63 mm |
| September | 14.3 °C | 24.5 °C | 86.61 mm |
| October | 7.8 °C | 17.5 °C | 102.36 mm |
| November | 1.7 °C | 9.9 °C | 78.74 mm |
| December | -3.9 °C | 3.3 °C | 59.44 mm |
| Annual | 6.2 °C | 15.3 °C | 1025.64 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 6a : -23.3°C to -20.6°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 |