Pleasant Plains, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.9 °C (low) to 17.2 °C (high). Annual precipitation averages 990.3 Millimeters. Pleasant Plains 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 | -7.6 °C | 1.7 °C | 53.85 mm |
| February | -5.7 °C | 4.4 °C | 48.51 mm |
| March | -0.6 °C | 10.9 °C | 67.56 mm |
| April | 5.4 °C | 17.9 °C | 101.6 mm |
| May | 11.7 °C | 23.4 °C | 117.09 mm |
| June | 16.9 °C | 28.1 °C | 116.59 mm |
| July | 18.6 °C | 29.8 °C | 98.81 mm |
| August | 17.4 °C | 29.1 °C | 89.15 mm |
| September | 12.8 °C | 26.1 °C | 85.09 mm |
| October | 6.4 °C | 19.2 °C | 80.26 mm |
| November | 0.4 °C | 11.2 °C | 75.69 mm |
| December | -4.6 °C | 4.6 °C | 56.13 mm |
| Annual | 5.9 °C | 17.2 °C | 990.33 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 |