USDA zone 4b in Minnesota
USDA plant hardiness zone 4b covers 76 locations across Minnesota (average annual extreme minimum −25 to −20 °F): Alexandria, MN, Appleton, MN, Austin, MN, Becker, MN, Belle Plaine, MN, Benson, MN, and 70 more. Average last spring frost across this group ranges April 23 (Credit River) to May 26 (Esko), and growing seasons run 118–177 days (Esko to Hugo) — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Minnesota location's own frost dates; the printable planting calendar uses East Bethel, this group's median-season location.
- USDA zone
- 4b−25 to −20 °F
- Last frost range
- Apr 23–May 26avg, 32°F
- First frost range
- Sep 23–Oct 20avg, 32°F
- Growing season range
- 118–177days
Locations in this group
Every location below shares this zone and a nearby weather station, but keeps its own frost dates — find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.
| Location | Also covers | Nearest station | Last frost | First frost | Season (days) |
|---|---|---|---|---|---|
| Alexandria | Garfield, Evansville, Ashby, Brandon, Kensington | Alexandria Muni Ap | May 2 | Oct 8 | 159 |
| Appleton | Milan, Watson | Milan 1nw | May 3 | Oct 2 | 151 |
| Austin | Lansing, Rose Creek, Waltham, Brownsdale | Austin Waste Wtp Facility | Apr 30 | Oct 5 | 158 |
| Becker | Big Lake, Princeton, Zimmerman | Santiago 3 E | May 7 | Sep 28 | 144 |
| Belle Plaine | New Prague, Elko New Market, Jordan, Lonsdale, Montgomery, Norwood Young America, +2 more | Jordan 1ssw | May 2 | Oct 5 | 153 |
| Benson | Clontarf, Kerkhoven, Danvers, Murdock | Benson | May 4 | Oct 3 | 151 |
| Braham | — | Mora | May 9 | Sep 30 | 142 |
| Brooten | Starbuck, Sedan, Lowry, Westport, Farwell | Glenwood 2wnw | May 11 | Sep 27 | 139 |
| Browns Valley | Graceville, Beardsley, Barry | Browns Valley | May 9 | Sep 28 | 141 |
| Canby | Ivanhoe | Canby | May 2 | Oct 5 | 156 |
| Chatfield | Preston, Harmony, Canton, Fountain, Wykoff, Whalan | Preston | May 14 | Sep 28 | 136 |
| Cokato | — | Dassel 3se | Apr 30 | Oct 10 | 162 |
| Corcoran | Medina | New Hope | Apr 29 | Oct 12 | 163 |
| Credit River | — | Mpls Flying Cloud Ap | Apr 23 | Oct 14 | 172 |
| Darfur | — | St James Wwtp | Apr 30 | Oct 7 | 160 |
| Dawson | Madison, Bellingham, Marietta | Madison Wwtp | May 3 | Oct 2 | 151 |
| Delano | Mayer, New Germany | Delano | Apr 30 | Oct 8 | 159 |
| Dovray | — | Tracy | May 2 | Oct 5 | 156 |
| Duluth | Poplar, Oliver | Superior | May 6 | Oct 9 | 154 |
| East Bethel * | Cambridge, Isanti, Bethel, Stanchfield | Cambridge | May 2 | Oct 4 | 153 |
| East Bethel | — | Cedar | May 1 | Oct 7 | 158 |
| Elba | — | Minnesota City Dam 5 | Apr 23 | Oct 16 | 175 |
| Elk River | — | Elk Rvr | May 4 | Oct 5 | 154 |
| Esko | — | Cloquet | May 26 | Sep 23 | 118 |
| Faribault | Northfield, Lonsdale, Dundas, Nerstrand | Faribault | May 5 | Oct 5 | 152 |
| Geneva | Hollandale, Conger | Albert Lea 3se | Apr 27 | Oct 9 | 164 |
| Glencoe | Gaylord, Arlington, Winthrop, Lafayette, Henderson, Green Isle, +5 more | Gaylord | Apr 24 | Oct 15 | 170 |
| Grand Marais | — | Grand Portage | May 24 | Sep 29 | 127 |
| Ham Lake | Ramsey | Andover 1n | May 5 | Oct 2 | 148 |
| Hendricks | Astoria | Astoria 4s | May 6 | Oct 3 | 150 |
| Hermantown | Proctor | Duluth | May 13 | Oct 1 | 140 |
| Hugo | Stillwater, Mahtomedi | Vadnais Lake | Apr 23 | Oct 20 | 177 |
| Hutchinson | Winsted, Lester Prairie, Buffalo Lake, Silver Lake | Hutchinson 1 N | Apr 28 | Oct 8 | 163 |
| Independence | Minnetrista, Chaska, Victoria, Waconia, Watertown, Norwood Young America, +2 more | Chanhassen Wsfo | Apr 30 | Oct 9 | 160 |
| Kimball | South Haven | Kimball 3n | May 2 | Oct 5 | 156 |
| Knife River | — | Two Harbors | May 12 | Oct 6 | 145 |
| Lakeville | Randolph, New Trier | Rosemount Rsch & Outreach Ctr | May 2 | Oct 5 | 155 |
| Leota | Edgerton, Ruthton, Woodstock | Lake Wilson | May 7 | Sep 29 | 145 |
| Litchfield | Darwin, Dassel, Eden Valley, Atwater, Cosmos, Watkins, +1 more | Litchfield | May 6 | Oct 2 | 147 |
| Lutsen | — | Wolf Ridge Elc | May 15 | Oct 1 | 137 |
| Mabel | — | Mabel | May 10 | Sep 28 | 140 |
| Minneapolis | — | Lower St Anthony Falls | Apr 23 | Oct 16 | 175 |
| Montevideo | Granite Falls, Clara, Clarkfield, Maynard, Boyd | Montevideo 1sw | May 4 | Oct 1 | 149 |
| Morris | Donnelly, Hoffman, Barrett, Hancock, Cyrus | Morris W Cntrl Rsch & Outreach | May 4 | Oct 1 | 150 |
| North Branch | Harris | Wild Rvr Sp | May 19 | Sep 25 | 128 |
| Olivia | Hector, Bird Island, Danube | Olivia 3e | May 6 | Oct 1 | 146 |
| Ortonville | Holloway, Odessa, Clinton, Chokio, Correll, Alberta | Artichoke Lake 1 E | May 1 | Oct 8 | 159 |
| Osakis | Burtrum, West Union | Long Prairie | May 13 | Sep 27 | 134 |
| Owatonna | Medford, Ellendale | Owatonna | May 5 | Oct 6 | 154 |
| Paynesville | New London, Belgrade, Spicer, Sunburg | New London | May 4 | Oct 4 | 152 |
| Pipestone | Lake Benton, Hardwick, Jasper, Holland, Ihlen | Pipestone | May 4 | Oct 2 | 152 |
| Red Wing | Cannon Falls, Frontenac, Diamond Bluff | Red Wing Dam 3 | Apr 23 | Oct 14 | 173 |
| Renville | Fairfax, Morton, Seaforth, Franklin, Sacred Heart, Belview, +1 more | Redwood Falls Muni Ap | Apr 30 | Oct 4 | 157 |
| Rochester | Pine Island, Kasson, Byron, Oronoco, Dodge Center, Mantorville, +1 more | Byron 4north | May 12 | Sep 28 | 139 |
| Rochester | Stewartville, Marion, Eyota, Dover | Rochester Intl Ap | Apr 30 | Oct 6 | 159 |
| Rogers | Dayton | Mpls Crystal Ap | Apr 30 | Oct 8 | 159 |
| Ronneby | Pease, Bock | Milaca | May 8 | Oct 1 | 143 |
| Rush | Siren | Grantsburg | May 11 | Oct 1 | 141 |
| Rushford | St. Charles, Lewiston, Utica, Peterson | Rushford | May 8 | Oct 3 | 147 |
| Sauk Centre | Upsala, Melrose, Freeport, St. Martin, Greenwald, Grey Eagle | Melrose | May 4 | Oct 1 | 148 |
| Scandia | Forest Lake, Chisago, Marine on St. Croix, Lindstrom, Somerset, Stacy, +1 more | Forest Lake 5ne | May 3 | Oct 5 | 154 |
| Spring Valley | Dexter, Elkton, Adams, Le Roy, Grand Meadow, Racine, +2 more | Grand Meadow | May 6 | Oct 1 | 146 |
| St. Cloud | Sartell, Sauk Rapids, Clearwater, Clear Lake | St Cloud Rgnl Ap | May 7 | Sep 30 | 144 |
| St. Cloud | Rockville, Waite Park, Sartell, St. Joseph, Cold Spring, Albany, +5 more | Collegeville St John's | May 3 | Oct 7 | 155 |
| St. Michael | Otsego, Greenfield, Monticello, Buffalo, Annandale, Montrose, +3 more | Buffalo 2ne | Apr 30 | Oct 9 | 163 |
| St. Paul | — | St Paul Downtown Ap | Apr 24 | Oct 16 | 174 |
| St. Peter | Le Sueur, Le Center | St Peter | May 2 | Oct 4 | 153 |
| Tyler | Wood Lake, Vesta, Hanley Falls | Marshall | May 5 | Oct 3 | 150 |
| Wabasha | Lake, Plainview, Stockholm, Elgin, Pepin, Zumbro Falls, +2 more | Theilman 1ssw | May 7 | Oct 2 | 148 |
| Wabasha | Alma, Nelson, Waumandee | Alma Dam 4 | Apr 28 | Oct 14 | 168 |
| Wabasso | Wanda | Lamberton Sw Rsch & Outreach C | May 3 | Oct 2 | 152 |
| Waseca | Waterville, Morristown, New Richland, Kilkenny | Waseca S Rsch & Outreach Ctr | May 2 | Oct 4 | 155 |
| Wells | — | Wells | Apr 30 | Oct 6 | 158 |
| Wheaton | Norcross, Elbow Lake, Herman, Dumont | Wheaton | May 1 | Oct 9 | 160 |
| Willmar | Pennock, Blomkest, Prinsburg, Raymond, Lake Lillian, Kandiyohi | Willmar Wwtp | Apr 30 | Oct 7 | 159 |
| Zumbrota | Kenyon, Wanamingo, Dennison, Goodhue, Mazeppa | Zumbrota | May 9 | Sep 30 | 144 |
* East Bethel is this group's median-season location — the calendar below is computed from its data.
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.
Planting calendar (East Bethel, representative)
Computed from East Bethel's average frost dates — the median-season location in this Minnesotazone 4b group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting | Season fit |
|---|---|---|---|---|---|---|
| Tomato | Tender | Mar 7 – Mar 21 | May 9 – May 16 | Jul 8 – Jul 28 | — | matures comfortably |
| Pepper | Very tender | Feb 21 – Mar 7 | May 16 – May 23 | Jul 15 – Aug 14 | — | matures comfortably |
| Cucumber | Tender | Apr 4 – Apr 11 | May 9 – May 16 | Jun 28 – Jul 18 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | May 9 – May 16 | Jun 23 – Jul 8 | — | matures comfortably |
| Bush bean | Tender | — | May 9 – May 16 | Jun 28 – Jul 8 | Aug 5 – Aug 15 | matures comfortably |
| Sweet corn | Tender | — | May 2 – May 16 | Jul 1 – Jul 31 | — | matures comfortably |
| Basil | Very tender | Mar 21 – Apr 4 | May 9 – May 16 | Jun 8 – Jun 23 | — | matures comfortably |
| Lettuce | Half-hardy | Mar 21 – Apr 4 | Apr 4 – Apr 18 | May 19 – Jun 3 | Jul 22 – Aug 6 | matures comfortably |
| Pea | Hardy | — | Mar 21 – Apr 4 | May 15 – May 30 | Jul 12 – Jul 27 | matures comfortably |
| Spinach | Hardy | — | Mar 21 – Apr 4 | Apr 30 – May 10 | Aug 1 – Aug 11 | matures comfortably |
| Carrot | Half-hardy | — | Apr 11 – Apr 18 | Jun 10 – Jun 30 | Jul 2 – Jul 22 | matures comfortably |
| Broccoli | Half-hardy | Mar 7 – Mar 21 | Apr 4 – Apr 18 | May 29 – Jun 18 | Jul 7 – Jul 27 | matures comfortably |
Which crops fit this growing season
Using East Bethel's own 153-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 12 of 12 crops mature here with comfortable margin. A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.
Frost & freeze dates (East Bethel)
From NOAA's 1991–2020 Climate Normals at station USC00211227. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | May 13 | May 28 | Sep 26 | Oct 10 | 133 |
| 32°F (freeze) | May 2 | May 20 | Oct 4 | Oct 19 | 153 |
| 28°F | Apr 21 | May 6 | Oct 15 | Nov 3 | 175 |
| 24°F | Apr 10 | Apr 25 | Oct 31 | Nov 13 | 200 |
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 76 locations is 2,513; East Bethel's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 2,484 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 4,382 | cool-season crops (brassicas, greens) |
Hardiness zone 4b in Minnesota
Zone 4b means an average annual extreme minimum winter temperature of about −25 to −20 °F on the USDA's 2023 map — the number that tells you which perennials, shrubs, and trees reliably survive an average winter here. It does not set your planting dates, which come from the frost calendar above. Minnesota spans 5 hardiness zones in this dataset — see all Minnesota locations for the full range, including zones3a, 3b, 4a, 5a.
Explore zone 4b in other states at zone 4b, or see all USDA hardiness zones.
Frequently asked questions
- What does USDA hardiness zone 4b mean in Minnesota?
- Zone 4b means an average annual extreme minimum winter temperature of −25 to −20 °F — the standard USDA measure of which perennials survive winter. 76 locations in Minnesota fall in this zone. It does not set planting dates; see the frost calendar below for that.
- Where in Minnesota's zone 4b is the growing season longest?
- Hugo runs the longest season on this page at about 177 days; Esko is shortest at about 118 days — they share the same hardiness zone, but they sit at different weather stations, so their frost calendars differ.
- When should I plant tomatoes in Minnesota's zone 4b?
- Using East Bethel's frost dates (this page's median-season location): start seeds indoors about Mar 7 – Mar 21, then transplant outside about May 9 – May 16. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
- Does every location in Minnesota's zone 4b have the same frost dates?
- No — they do not all share a weather station, so frost dates vary by a week or more across the 76 locations listed (see the table above for each location's own dates).
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.