USDA hardiness zone 4b
USDA plant hardiness zone 4b covers areas whose average annual extreme minimum winter temperature is −25 to −20 °F — the standard USDA measure of which perennials survive an average winter. Hardiness zone sets winter survival, but planting DATES depend on your local frost calendar, which varies within a zone. 435 locations on this site fall in zone 4b (Abbotsford, WI, Akaska, SD, Alamosa, CO, Alexandria, MN, Alpena, SD, Altona, NY, Alzada, MT, Alzada, MT, and 427 more); open one to see its frost dates, growing-season length, and a printable per-crop planting calendar.
Locations in zone 4b — 60 of 435
| Location | Last frost | First frost | Season (days) |
|---|---|---|---|
| Abbotsford, WI | May 11 | Oct 1 | 141 |
| Alzada, MT | May 17 | Sep 22 | 127 |
| Arlington, SD | May 3 | Oct 2 | 151 |
| Augusta, WI | May 7 | Oct 1 | 146 |
| Balsam Lake, WI | May 6 | Oct 4 | 149 |
| Benson, MN | May 4 | Oct 3 | 151 |
| Big Sky, MT | Jun 16 | Sep 4 | 78 |
| Black River Falls, WI | May 10 | Oct 1 | 144 |
| Brimley, MI | May 22 | Oct 4 | 136 |
| Bruce, WI | May 9 | Sep 29 | 140 |
| Camp Three, MT | May 20 | Sep 21 | 124 |
| Chatham, MI | May 16 | Oct 14 | 148 |
| Cokato, MN | Apr 30 | Oct 10 | 162 |
| Cornell, WI | May 5 | Oct 2 | 149 |
| Custer, MT | May 26 | Sep 16 | 111 |
| Delaware, IA | May 3 | Oct 4 | 154 |
| Eagle Lake, ME | Jun 2 | Sep 15 | 102 |
| Edgemont, SD | May 23 | Sep 20 | 117 |
| Esko, MN | May 26 | Sep 23 | 118 |
| Floweree, MT | May 23 | Sep 23 | 120 |
| Galesville, WI | Apr 29 | Oct 11 | 165 |
| Geyser, MT | May 22 | Sep 23 | 123 |
| Goodman, WI | May 24 | Sep 30 | 128 |
| Greenville, ME | May 23 | Sep 29 | 128 |
| Hankinson, ND | May 4 | Oct 3 | 152 |
| Hebgen Lake Estates, MT | Jun 15 | Sep 10 | 87 |
| Hettinger, ND | May 30 | Sep 11 | 103 |
| Houlton, ME | May 27 | Sep 18 | 115 |
| Iliamna, AK | May 10 | Oct 1 | 144 |
| Jardine, MT | May 21 | Sep 27 | 128 |
| Judith Gap, MT | May 28 | Sep 20 | 112 |
| Kingfield, ME | May 24 | Sep 21 | 118 |
| LaMoure, ND | May 10 | Sep 28 | 140 |
| Leola, SD | May 9 | Sep 28 | 141 |
| Long Lake, WI | Jun 4 | Sep 10 | 95 |
| Madison, SD | May 5 | Sep 30 | 148 |
| Mass, MI | May 27 | Oct 1 | 127 |
| Menomonie, WI | May 9 | Oct 1 | 143 |
| Morristown, SD | May 20 | Sep 23 | 124 |
| Neopit, WI | May 9 | Oct 2 | 144 |
| North Branch, MN | May 19 | Sep 25 | 128 |
| Ontario, WI | Apr 27 | Oct 14 | 170 |
| Parkman, WY | May 16 | Sep 24 | 130 |
| Poplar, WI | May 24 | Sep 26 | 124 |
| Rapelje, MT | May 24 | Sep 21 | 116 |
| Rice Lake, WI | May 8 | Oct 2 | 145 |
| Rockport Colony, MT | Jun 9 | Sep 3 | 86 |
| Sauk Centre, MN | May 4 | Oct 1 | 148 |
| Shepherd, MT | May 12 | Sep 25 | 136 |
| Skwentna, AK | Jun 2 | Sep 8 | 98 |
| Speculator, NY | May 18 | Sep 30 | 134 |
| St. Michael, MN | Apr 30 | Oct 9 | 163 |
| Sundance, WY | May 21 | Sep 25 | 124 |
| Tomahawk, WI | May 11 | Sep 30 | 139 |
| Upton, WY | May 20 | Sep 23 | 123 |
| Wabasso, MN | May 3 | Oct 2 | 152 |
| Wasta, SD | May 8 | Oct 3 | 146 |
| Wells River, VT | May 15 | Sep 28 | 133 |
| White Sulphur Springs, MT | Jun 4 | Sep 11 | 97 |
| Winfred, SD | May 6 | Oct 3 | 151 |
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
What zone 4b means for your garden
A plant rated "hardy to zone 4b" can be expected to survive a winter whose coldest night lands in the −25 to −20 °F range — the metric the USDA map is built on. That governs perennials, shrubs, and trees. For annual vegetables, what matters is the frost calendar: the dates of the average last spring and first fall freeze, which set when it is safe to plant and how long the season runs. Those come from the individual location pages above.
Zones are from the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP — see the methodology page. Browse all hardiness zones or crop-by-crop timing.
Frequently asked questions
- What temperature range is USDA zone 4b?
- Zone 4b covers areas whose average annual extreme minimum winter temperature is −25 to −20 °F. Each numbered zone is a 10°F band; the "a" and "b" half-zones split it into 5°F steps.
- Does zone 4b tell me when to plant?
- No — the hardiness zone tells you which perennials survive winter, not when to sow annual vegetables. Planting dates depend on your local last and first frost, which can vary within a single zone. Open one of the sample locations in zone 4b to see its frost calendar and per-crop planting windows.
- What can I grow in zone 4b?
- Almost any common vegetable can be grown in zone 4b; what changes with zone and local climate is the timing and the length of the season. Cold-hardy crops (peas, spinach, lettuce) go out earliest, tender crops (tomatoes, peppers, basil) after the last frost. Use each location's calendar for exact dates.