Amboy, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 38.9 °F (low) to 59.1 °F (high). Annual precipitation averages 38.1 Inches. Amboy 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 | 13.1 °F | 29.4 °F | 1.78 in. |
| February | 16.8 °F | 34.0 °F | 1.76 in. |
| March | 27.0 °F | 46.6 °F | 2.4 in. |
| April | 37.4 °F | 60.2 °F | 3.5 in. |
| May | 49.4 °F | 71.6 °F | 4.83 in. |
| June | 59.2 °F | 80.5 °F | 5.21 in. |
| July | 62.5 °F | 83.3 °F | 4.15 in. |
| August | 60.3 °F | 81.7 °F | 3.93 in. |
| September | 52.1 °F | 76.0 °F | 3.41 in. |
| October | 40.4 °F | 63.1 °F | 2.77 in. |
| November | 29.6 °F | 47.8 °F | 2.28 in. |
| December | 19.3 °F | 34.9 °F | 2.03 in. |
| Annual | 38.9 °F | 59.1 °F | 38.05 in. |
| 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 : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |