Lost Nation, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.7 °C (low) to 14.7 °C (high). Annual precipitation averages 980.7 Millimeters. Lost Nation 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 | -10.8 °C | -1.7 °C | 44.7 mm |
| February | -8.7 °C | 0.7 °C | 44.2 mm |
| March | -2.9 °C | 7.7 °C | 61.47 mm |
| April | 2.9 °C | 15.3 °C | 93.22 mm |
| May | 9.6 °C | 21.6 °C | 121.92 mm |
| June | 15.1 °C | 26.6 °C | 129.79 mm |
| July | 16.9 °C | 28.1 °C | 108.2 mm |
| August | 15.7 °C | 27.3 °C | 101.6 mm |
| September | 11.1 °C | 24.1 °C | 90.93 mm |
| October | 4.6 °C | 16.9 °C | 73.91 mm |
| November | -1.5 °C | 8.4 °C | 59.18 mm |
| December | -7.2 °C | 1.4 °C | 51.56 mm |
| Annual | 3.7 °C | 14.7 °C | 980.68 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |