Lockport, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5 °C (low) to 15.6 °C (high). Annual precipitation averages 1021.6 Millimeters. Lockport is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.7 °C | -0.2 °C | 54.61 mm |
| February | -7.1 °C | 2.1 °C | 50.55 mm |
| March | -1.8 °C | 8.6 °C | 64.52 mm |
| April | 3.9 °C | 15.8 °C | 100.33 mm |
| May | 10 °C | 21.9 °C | 123.19 mm |
| June | 15.6 °C | 27.2 °C | 119.63 mm |
| July | 17.8 °C | 29.2 °C | 109.73 mm |
| August | 17.1 °C | 28.2 °C | 107.7 mm |
| September | 12.7 °C | 24.9 °C | 84.84 mm |
| October | 6 °C | 17.7 °C | 88.14 mm |
| November | 0 °C | 9.6 °C | 62.74 mm |
| December | -5.5 °C | 2.7 °C | 55.63 mm |
| Annual | 5 °C | 15.6 °C | 1021.61 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| 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 |