| 2023 Hardiness Zone: | Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 1b: -15F to -10F |
| Average First Frost Date: | Oct. 1 - Oct. 10 |
| Average Last Frost Date: | May 11 - May 20 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 53d - Lake Michigan Lacustrine Clay Plain |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 53073 - Plymouth, WI | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 9 | 14 | 23 | 34 | 45 | 55 | 60 | 59 | 50 | 40 | 28 | 16 | 36 |
| Avg Max Temp (°F) | 25 | 30 | 41 | 54 | 68 | 77 | 81 | 79 | 71 | 59 | 43 | 30 | 55 |
| Avg Precip (In.) | 1.42 | 1.25 | 2.4 | 3.46 | 3.62 | 3.89 | 3.93 | 4.53 | 3.99 | 2.92 | 2.84 | 1.88 | 36.12 |