| 2023 Hardiness Zone: | Zone 4b: -25°F to -20°F Zone 4a: -30°F to -25°F | |
| 2012 Hardiness Zone: | Zone 4b: -25°F to -20°F Zone 4a: -30°F to -25°F | |
| 1990 Hardiness Zone: | Zone 4b: -25F to -20F | |
| Average First Frost Date: | Oct. 1 - Oct. 10 | |
| Average Last Frost Date: | May 21 - May 31 | |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year | |
| Ecoregion: | 50p - Toimi Drumlins | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 55810 - Duluth, MN | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | -1 | 6 | 17 | 29 | 40 | 49 | 55 | 55 | 46 | 35 | 22 | 6 | 30 |
| Avg Max Temp (°F) | 18 | 25 | 35 | 49 | 63 | 71 | 77 | 74 | 65 | 53 | 36 | 23 | 49 |
| Avg Precip (In.) | 1.08 | .78 | 1.64 | 2.01 | 2.85 | 4.12 | 4.14 | 4.08 | 3.97 | 2.39 | 2.02 | .94 | 30.02 |