USDA zone 5a in Minnesota
USDA plant hardiness zone 5a covers 40 locations across Minnesota (average annual extreme minimum −20 to −15 °F): Albert Lea, MN, Bayport, MN, Blaine, MN, Blooming Prairie, MN, Bloomington, MN, Blue Earth, MN, and 34 more. Average last spring frost across this group ranges April 23 (Bloomington) to May 12 (Hayfield), and growing seasons run 139–180 days (Hayfield to Homer) — 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 Blaine, this group's median-season location.
- USDA zone
- 5a−20 to −15 °F
- Last frost range
- Apr 23–May 12avg, 32°F
- First frost range
- Sep 28–Oct 21avg, 32°F
- Growing season range
- 139–180days
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) |
|---|---|---|---|---|---|
| Albert Lea | Emmons, Hayward, Clarks Grove, Twin Lakes, Myrtle | Albert Lea 3se | Apr 27 | Oct 9 | 164 |
| Bayport | Lakeland Shores | River Falls | May 11 | Oct 1 | 143 |
| Blaine * | Maple Grove, Brooklyn Park, Coon Rapids, Fridley, Champlin, Brooklyn Center, +3 more | Mpls Crystal Ap | Apr 30 | Oct 8 | 159 |
| Blooming Prairie | Claremont | Owatonna | May 5 | Oct 6 | 154 |
| Bloomington | Eden Prairie, Shakopee, Minnetonka, Savage, Edina | Mpls Flying Cloud Ap | Apr 23 | Oct 14 | 172 |
| Blue Earth | Winnebago, Delavan | Winnebago | Apr 27 | Oct 10 | 166 |
| Caledonia | Spring Grove, Hokah, Eitzen | Caledonia | Apr 29 | Oct 10 | 165 |
| Chanhassen | Orono, Shorewood | Chanhassen Wsfo | Apr 30 | Oct 9 | 160 |
| Duluth | — | Superior | May 6 | Oct 9 | 154 |
| Fairmont | Welcome, Truman, Granada, Ceylon, Northrop | Fairmont | Apr 25 | Oct 14 | 171 |
| Garden | Lake Crystal, Mapleton, Good Thunder, Vernon Center, Amboy | Amboy | Apr 30 | Oct 7 | 161 |
| Hayfield | — | Byron 4north | May 12 | Sep 28 | 139 |
| Homer | — | Winona Dam 5 A | Apr 23 | Oct 21 | 180 |
| Houston | — | Rushford | May 8 | Oct 3 | 147 |
| Jackson | Lakefield, Okabena, Alpha | Lakefield 2ne | May 2 | Oct 2 | 153 |
| Janesville | St. Clair, Pemberton | Waseca S Rsch & Outreach Ctr | May 2 | Oct 4 | 155 |
| Lyle | — | Austin Waste Wtp Facility | Apr 30 | Oct 5 | 158 |
| Marshall | Minneota, Lynd, Cottonwood, Russell, Ghent, Arco, +1 more | Marshall | May 5 | Oct 3 | 150 |
| Minneapolis | St. Paul, Roseville, Falcon Heights | U Of Mn St Paul | Apr 28 | Oct 8 | 162 |
| Minneapolis | Plymouth, Minnetonka, St. Louis Park, Golden Valley | New Hope | Apr 29 | Oct 12 | 163 |
| Minneapolis | Bloomington, Eagan, Burnsville, Edina, Mendota Heights, Richfield, +1 more | Minneapolis/st Paul Ap | Apr 23 | Oct 18 | 176 |
| Minneapolis | St. Anthony | Lower St Anthony Falls | Apr 23 | Oct 16 | 175 |
| Minnesota Lake | Alden, Easton, Frost, Kiester, Waldorf, Bricelyn, +2 more | Wells | Apr 30 | Oct 6 | 158 |
| New Ulm | Courtland, Essig | New Ulm 2 Se | Apr 29 | Oct 7 | 161 |
| North Mankato | Eagle Lake, Madison Lake, Kasota, Elysian, Nicollet, Cleveland, +1 more | St Peter | May 2 | Oct 4 | 153 |
| Porter | Taunton | Canby | May 2 | Oct 5 | 156 |
| Redwood Falls | Morgan | Redwood Falls Muni Ap | Apr 30 | Oct 4 | 157 |
| Rosemount | Eagan, Inver Grove Heights, Burnsville, Apple Valley, Farmington, Vermillion | Rosemount Rsch & Outreach Ctr | May 2 | Oct 5 | 155 |
| Sanborn | Springfield, Sleepy Eye, Comfrey, Clements | Springfield 1 Nw | May 4 | Oct 1 | 150 |
| Sargeant | — | Grand Meadow | May 6 | Oct 1 | 146 |
| Sherburn | — | Sherburn 3wsw | Apr 28 | Oct 8 | 162 |
| Slayton | Kenneth, Chandler, Wilmont, Iona, Lake Wilson, Lismore | Lake Wilson | May 7 | Sep 29 | 145 |
| St. James | Madelia, Trimont, Butterfield, Odin, Ormsby, Hanska, +2 more | St James Wwtp | Apr 30 | Oct 7 | 160 |
| St. Paul | Woodbury, Inver Grove Heights, Lake Elmo, South St. Paul, Newport, Landfall | St Paul Downtown Ap | Apr 24 | Oct 16 | 174 |
| St. Paul | Blaine, Lino Lakes, Grant, Maplewood, Shoreview, Arden Hills, +2 more | Vadnais Lake | Apr 23 | Oct 20 | 177 |
| Tracy | Balaton, Avoca, Garvin, Dovray | Tracy | May 2 | Oct 5 | 156 |
| Walnut Grove | Lamberton, Westbrook, Revere, Lucan | Lamberton Sw Rsch & Outreach C | May 3 | Oct 2 | 152 |
| Windom | Mountain Lake, Heron Lake, Bingham Lake, Jeffers, Storden | Windom | Apr 30 | Oct 10 | 162 |
| Woodbury | Cottage Grove, Afton, Hastings, St. Paul Park | Hastings Dam 2 | Apr 23 | Oct 19 | 177 |
| Worthington | Brewster, Fulda, Wilmont, Rushmore | Worthington 2 Nne | May 3 | Oct 4 | 153 |
* Blaine 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 (Blaine, representative)
Computed from Blaine's average frost dates — the median-season location in this Minnesotazone 5a 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 5 – Mar 19 | May 7 – May 14 | Jul 6 – Jul 26 | — | matures comfortably |
| Pepper | Very tender | Feb 19 – Mar 5 | May 14 – May 21 | Jul 13 – Aug 12 | — | matures comfortably |
| Cucumber | Tender | Apr 2 – Apr 9 | May 7 – May 14 | Jun 26 – Jul 16 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | May 7 – May 14 | Jun 21 – Jul 6 | — | matures comfortably |
| Bush bean | Tender | — | May 7 – May 14 | Jun 26 – Jul 6 | Aug 9 – Aug 19 | matures comfortably |
| Sweet corn | Tender | — | Apr 30 – May 14 | Jun 29 – Jul 29 | — | matures comfortably |
| Basil | Very tender | Mar 19 – Apr 2 | May 7 – May 14 | Jun 6 – Jun 21 | — | matures comfortably |
| Lettuce | Half-hardy | Mar 19 – Apr 2 | Apr 2 – Apr 16 | May 17 – Jun 1 | Jul 26 – Aug 10 | matures comfortably |
| Pea | Hardy | — | Mar 19 – Apr 2 | May 13 – May 28 | Jul 16 – Jul 31 | matures comfortably |
| Spinach | Hardy | — | Mar 19 – Apr 2 | Apr 28 – May 8 | Aug 5 – Aug 15 | matures comfortably |
| Carrot | Half-hardy | — | Apr 9 – Apr 16 | Jun 8 – Jun 28 | Jul 6 – Jul 26 | matures comfortably |
| Broccoli | Half-hardy | Mar 5 – Mar 19 | Apr 2 – Apr 16 | May 27 – Jun 16 | Jul 11 – Jul 31 | matures comfortably |
Which crops fit this growing season
Using Blaine's own 159-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 (Blaine)
From NOAA's 1991–2020 Climate Normals at station USW00094960. 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 9 | May 26 | Sep 29 | Oct 11 | 141 |
| 32°F (freeze) | Apr 30 | May 17 | Oct 8 | Oct 21 | 159 |
| 28°F | Apr 20 | May 5 | Oct 18 | Nov 1 | 179 |
| 24°F | Apr 9 | Apr 23 | Oct 30 | Nov 12 | 201 |
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 40 locations is 2,648; Blaine's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 2,755 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 4,707 | cool-season crops (brassicas, greens) |
Hardiness zone 5a in Minnesota
Zone 5a means an average annual extreme minimum winter temperature of about −20 to −15 °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, 4b.
Explore zone 5a in other states at zone 5a, or see all USDA hardiness zones.
Frequently asked questions
- What does USDA hardiness zone 5a mean in Minnesota?
- Zone 5a means an average annual extreme minimum winter temperature of −20 to −15 °F — the standard USDA measure of which perennials survive winter. 40 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 5a is the growing season longest?
- Homer runs the longest season on this page at about 180 days; Hayfield is shortest at about 139 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 5a?
- Using Blaine's frost dates (this page's median-season location): start seeds indoors about Mar 5 – Mar 19, then transplant outside about May 7 – May 14. 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 5a 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 40 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.