USDA hardiness zone 4b
In zone 4b the average coldest winter night reaches -25°F to -20°F. Plants labeled for zone 4 (or a colder zone) can survive the winter outdoors here. 52 U.S. cities with 10,000+ residents are in this zone.
| City | State | Zone | Avg. last frost | Avg. first frost |
|---|---|---|---|---|
| Rochester | MN | 4b | Apr 30 | Oct 6 |
| Duluth | MN | 4b | May 14 | Oct 12 |
| Plymouth | MN | 4b | Apr 29 | Oct 12 |
| Eau Claire | WI | 4b | Apr 24 | Oct 14 |
| Saint Cloud | MN | 4b | May 7 | Sep 30 |
| Lakeville | MN | 4b | Apr 27 | Oct 10 |
| Great Falls | MT | 4b | May 6 | Oct 1 |
| Wausau | WI | 4b | May 6 | Oct 4 |
| Butte | MT | 4b | Jun 13 | Sep 5 |
| Andover | MN | 4b | May 5 | Oct 2 |
| Ramsey | MN | 4b | May 4 | Oct 5 |
| Owatonna | MN | 4b | May 5 | Oct 6 |
| Prior Lake | MN | 4b | Apr 23 | Oct 14 |
| Chaska | MN | 4b | May 5 | Oct 5 |
| Austin | MN | 4b | Apr 30 | Oct 5 |
| Elk River | MN | 4b | May 4 | Oct 5 |
| Brookings | SD | 4b | May 6 | Oct 1 |
| Faribault | MN | 4b | May 5 | Oct 5 |
| Watertown | SD | 4b | May 7 | Sep 30 |
| Northfield | MN | 4b | May 5 | Oct 5 |
| Willmar | MN | 4b | Apr 30 | Oct 7 |
| Forest Lake | MN | 4b | May 3 | Oct 5 |
| Stillwater | MN | 4b | Apr 22 | Oct 19 |
| Marshfield | WI | 4b | May 5 | Oct 5 |
| Wisconsin Rapids | WI | 4b | May 9 | Sep 30 |
| Sartell | MN | 4b | May 7 | Sep 30 |
| Red Wing | MN | 4b | Apr 23 | Oct 14 |
| Saint Michael | MN | 4b | May 4 | Oct 5 |
| Menomonie | WI | 4b | May 9 | Oct 1 |
| Ham Lake | MN | 4b | May 5 | Oct 2 |
| Buffalo | MN | 4b | Apr 30 | Oct 9 |
| Otsego | MN | 4b | May 4 | Oct 5 |
| Jamestown | ND | 4b | May 8 | Sep 29 |
| River Falls | WI | 4b | May 11 | Oct 1 |
| Weston | WI | 4b | May 6 | Oct 4 |
| Hugo | MN | 4b | Apr 23 | Oct 20 |
| Chippewa Falls | WI | 4b | May 8 | Oct 4 |
| Hutchinson | MN | 4b | Apr 28 | Oct 8 |
| Sauk Rapids | MN | 4b | May 7 | Sep 30 |
| Huron | SD | 4b | May 6 | Oct 2 |
| Monticello | MN | 4b | Apr 30 | Oct 9 |
| Rogers | MN | 4b | May 4 | Oct 5 |
| Steamboat Springs | CO | 4b | Jun 9 | Sep 12 |
| Plover | WI | 4b | May 4 | Oct 7 |
| Waconia | MN | 4b | May 5 | Oct 5 |
| Alexandria | MN | 4b | May 2 | Oct 8 |
| East Bethel | MN | 4b | May 1 | Oct 7 |
| Riverton | WY | 4b | May 12 | Sep 24 |
| Massena | NY | 4b | May 8 | Oct 1 |
| Jackson | WY | 4b | Jun 20 | Aug 31 |
| Big Lake | MN | 4b | May 4 | Oct 5 |
| North Branch | MN | 4b | May 19 | Sep 25 |