Apple River, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 37.6 °F (low) to 57 °F (high). Annual precipitation averages 38.9 Inches. Apple River is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 10.9 °F | 27.2 °F | 1.41 in. |
| February | 14.3 °F | 31.5 °F | 1.59 in. |
| March | 25.3 °F | 44.0 °F | 2.17 in. |
| April | 36.2 °F | 57.7 °F | 3.91 in. |
| May | 48.0 °F | 69.4 °F | 4.38 in. |
| June | 58.1 °F | 78.8 °F | 5.72 in. |
| July | 61.7 °F | 81.9 °F | 4.67 in. |
| August | 59.5 °F | 80.2 °F | 4.15 in. |
| September | 51.2 °F | 73.7 °F | 3.71 in. |
| October | 39.6 °F | 60.9 °F | 2.96 in. |
| November | 28.6 °F | 45.7 °F | 2.41 in. |
| December | 17.6 °F | 32.8 °F | 1.8 in. |
| Annual | 37.6 °F | 57 °F | 38.88 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |