| 2023 Hardiness Zone: | Zone 3b: -35°F to -30°F Zone 4b: -25°F to -20°F Zone 4a: -30°F to -25°F | |
| 2012 Hardiness Zone: | Zone 3b: -35°F to -30°F Zone 3a: -40°F to -35°F 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 55803 - Duluth, MN | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | -2 | 5 | 16 | 29 | 40 | 49 | 55 | 54 | 45 | 34 | 21 | 5 | 29 |
| Avg Max Temp (°F) | 18 | 24 | 34 | 49 | 63 | 71 | 76 | 74 | 65 | 52 | 35 | 22 | 49 |
| Avg Precip (In.) | 1.12 | .8 | 1.65 | 1.99 | 2.83 | 4.23 | 4.26 | 4.05 | 3.85 | 2.32 | 2.01 | .98 | 30.08 |