Barrington, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.3 °F (low) to 58.6 °F (high). Annual precipitation averages 39 Inches. Barrington 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 | 14.5 °F | 30.3 °F | 1.97 in. |
| February | 17.2 °F | 34.2 °F | 1.94 in. |
| March | 26.7 °F | 45.7 °F | 2.25 in. |
| April | 37.0 °F | 58.3 °F | 3.8 in. |
| May | 47.9 °F | 69.6 °F | 4.91 in. |
| June | 57.8 °F | 79.6 °F | 4.69 in. |
| July | 62.9 °F | 83.8 °F | 3.86 in. |
| August | 61.5 °F | 81.5 °F | 4.19 in. |
| September | 53.3 °F | 74.7 °F | 3.49 in. |
| October | 41.7 °F | 61.9 °F | 3.28 in. |
| November | 30.6 °F | 47.6 °F | 2.45 in. |
| December | 20.5 °F | 35.5 °F | 2.15 in. |
| Annual | 39.3 °F | 58.6 °F | 38.98 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 | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |