Lewiston, Minnesota has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2 °C (low) to 12.2 °C (high). Annual precipitation averages 904.2 Millimeters. Lewiston is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14 °C | -4.9 °C | 27.69 mm |
| February | -12.1 °C | -2.4 °C | 23.88 mm |
| March | -5.1 °C | 4.5 °C | 48.26 mm |
| April | 1.4 °C | 12.4 °C | 93.47 mm |
| May | 8.3 °C | 19.2 °C | 118.11 mm |
| June | 14.1 °C | 24.7 °C | 139.19 mm |
| July | 16.1 °C | 26.7 °C | 107.44 mm |
| August | 14.7 °C | 25.6 °C | 111 mm |
| September | 10.1 °C | 21.8 °C | 95.5 mm |
| October | 3.2 °C | 14.3 °C | 62.99 mm |
| November | -3.3 °C | 5.6 °C | 44.2 mm |
| December | -9.8 °C | -1.7 °C | 32.51 mm |
| Annual | 2 °C | 12.2 °C | 904.24 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |