Triumph, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.8 °F (low) to 59.9 °F (high). Annual precipitation averages 37.8 Inches. Triumph 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 | 14.3 °F | 30.5 °F | 1.79 in. |
| February | 18.1 °F | 35.1 °F | 1.74 in. |
| March | 27.7 °F | 47.5 °F | 2.37 in. |
| April | 38.2 °F | 61.0 °F | 3.6 in. |
| May | 49.9 °F | 72.3 °F | 4.63 in. |
| June | 59.7 °F | 81.2 °F | 4.68 in. |
| July | 63.1 °F | 84.0 °F | 4.12 in. |
| August | 61.0 °F | 82.2 °F | 3.89 in. |
| September | 52.9 °F | 76.7 °F | 3.46 in. |
| October | 41.3 °F | 64.0 °F | 3.07 in. |
| November | 30.5 °F | 48.7 °F | 2.5 in. |
| December | 20.3 °F | 35.9 °F | 1.99 in. |
| Annual | 39.8 °F | 59.9 °F | 37.84 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 |