Hardiness zone 5a · 244 stations
Zone 5a Frost Dates: Typical Last Frost May 5
Summary across 244 NOAA weather stations whose location falls in zone 5a*. Dates are the typical (50% chance) frost dates of each station; the table shows the spread between stations.
- Typical last frostMay 5median station, 50% chance
- Typical first fall frostOctober 4median station, 50% chance
- Frost-free season151 daysmedian station
- Weather stations244dates differ by weeks inside a zone
| 25% of stations | Median station | 75% of stations | |
|---|---|---|---|
| Last frost in spring (32°F) | April 30 | May 5 | May 15 |
| First frost in fall (32°F) | September 30 | October 4 | October 8 |
| Frost-free days | 136 | 151 | 160 |
Frost dates inside one zone differ by weeks: the zone describes winter cold, not the length of the season. Use the station closest to you.
Stations in zone 5a
| Station | Zone | Last spring frost (50%) | First fall frost (50%) | Frost-free days |
|---|---|---|---|---|
| Academy, SD | 5a | April 30 | October 8 | 159 |
| Albert Lea, MN | 5a | April 27 | October 9 | 164 |
| Alexandria, SD | 5a | May 8 | September 29 | 143 |
| Allison, IA | 5a | April 27 | October 8 | 165 |
| Alta, WY | 5a | June 14 | September 11 | 85 |
| Amboy, MN | 5a | April 30 | October 7 | 161 |
| Ames, IA | 5a | April 23 | October 14 | 173 |
| Anselmo, NE | 5a | May 10 | October 1 | 143 |
| Arlington, WI | 5a | May 4 | October 6 | 154 |
| Atkinson, NE | 5a | May 4 | October 4 | 152 |
| Atlantic, IA | 5a | April 30 | October 2 | 153 |
| Audubon, IA | 5a | May 2 | October 3 | 154 |
| Bailey, CO | 5a | June 16 | September 8 | 84 |
| Bangor, ME | 5a | May 4 | October 4 | 152 |
| Bates Creek #2, WY | 5a | May 22 | September 26 | 125 |
| Beaver Dam, WI | 5a | May 2 | October 9 | 157 |
| Belle Fourche, SD | 5a | May 10 | September 30 | 143 |
| Belle Plaine, IA | 5a | April 28 | October 10 | 165 |
| Berlin, NH | 5a | May 14 | September 30 | 135 |
| Bern, ID | 5a | June 17 | September 3 | 77 |
| Biddle, MT | 5a | May 14 | September 28 | 134 |
| Big Timber, MT | 5a | May 14 | September 26 | 133 |
| Billings, MT | 5a | May 10 | October 1 | 142 |
| Bison, SD | 5a | May 10 | October 1 | 144 |
| Boone, IA | 5a | April 28 | October 12 | 165 |
| Boonville, NY | 5a | May 10 | October 4 | 145 |
| Bridgeport, NE | 5a | May 8 | October 3 | 147 |
| Bridgewater, SD | 5a | April 30 | October 7 | 161 |
| Bridgton, ME | 5a | May 5 | October 5 | 151 |
| Brodhead, WI | 5a | April 29 | October 12 | 165 |
| Broken Bow, NE | 5a | May 10 | October 1 | 142 |
| Buffalo, WY | 5a | May 24 | September 21 | 118 |
| Burlington, VT | 5a | April 29 | October 15 | 169 |
| Butte, NE | 5a | May 4 | October 6 | 152 |
| Cadillac, MI | 5a | May 19 | October 1 | 135 |
| Caledonia, MN | 5a | April 29 | October 10 | 165 |
| Canby, MN | 5a | May 2 | October 5 | 156 |
| Carroll, IA | 5a | April 27 | October 10 | 166 |
| Cascade, IA | 5a | April 28 | October 10 | 164 |
| Casper, WY | 5a | May 26 | September 22 | 117 |
| Cedar Rapids, IA | 5a | April 27 | October 11 | 165 |
| Centerville, SD | 5a | May 2 | October 1 | 151 |
| Chadron, NE | 5a | May 15 | September 28 | 133 |
| Chama, NM | 5a | June 14 | September 18 | 93 |
| Chamberlain, SD | 5a | May 3 | October 7 | 156 |
| Chanhassen, MN | 5a | April 30 | October 9 | 160 |
| Charles City, IA | 5a | April 30 | October 6 | 157 |
| Chatham Experiment Farm 2, MI | 5a | May 30 | September 27 | 119 |
| Cherokee, IA | 5a | May 4 | October 4 | 152 |
| Chilly Barton Flat, ID | 5a | June 14 | September 8 | 86 |
| Chugwater, WY | 5a | May 18 | September 24 | 129 |
| Clintonville, WI | 5a | May 4 | October 6 | 154 |
| Cody, WY | 5a | May 12 | October 1 | 140 |
| Cornwall, VT | 5a | May 5 | October 3 | 151 |
| Crofton, NE | 5a | April 30 | October 8 | 160 |
| Custer, SD | 5a | May 18 | September 28 | 129 |
| Dannemora, NY | 5a | May 6 | October 11 | 157 |
| Denison, IA | 5a | April 27 | October 11 | 166 |
| Dillon (Airport), MT | 5a | June 2 | September 13 | 101 |
| Dodgeville, WI | 5a | May 3 | October 7 | 157 |
| Dubuque, IA | 5a | April 28 | October 11 | 165 |
| Dubuque Lock and Dam 11, IA | 5a | April 19 | October 21 | 184 |
| Dupree 15 SSE, SD | 5a | May 6 | October 2 | 148 |
| Eagle Nest, NM | 5a | June 16 | September 14 | 87 |
| Eldora, IA | 5a | April 27 | October 10 | 165 |
| Elm Springs, SD | 5a | May 8 | October 3 | 146 |
| Elsmere, NE | 5a | May 6 | October 3 | 150 |
| Emblem, WY | 5a | May 12 | September 28 | 136 |
| Ennis, MT | 5a | June 16 | September 4 | 78 |
| Estherville, IA | 5a | May 2 | October 3 | 153 |
| Ewing, NE | 5a | May 7 | September 30 | 144 |
| Farmington, ME | 5a | May 16 | September 26 | 130 |
| Fayette, IA | 5a | May 4 | October 4 | 151 |
| Forest City, IA | 5a | April 30 | October 7 | 159 |
| Fort Dodge, IA | 5a | April 28 | October 8 | 162 |
| Franklinville, NY | 5a | May 14 | October 6 | 144 |
| Gaylord, MI | 5a | May 25 | September 26 | 125 |
| Gaylord, MN | 5a | April 24 | October 15 | 170 |
| Genoa Dam 8, WI | 5a | April 22 | October 17 | 178 |
| Gibbs Ranch - Jarbidge 24 SE, NV | 5a | June 4 | September 15 | 101 |
| Glens Falls, NY | 5a | May 9 | September 30 | 143 |
| Gordon, NE | 5a | May 11 | October 2 | 142 |
| Grand Marais, MN | 5a | May 20 | October 5 | 137 |
| Grayling, MI | 5a | May 23 | September 27 | 124 |
| Greeley, NE | 5a | May 5 | October 2 | 149 |
| Gregory, SD | 5a | May 6 | October 3 | 149 |
| Grinnell, IA | 5a | May 3 | October 6 | 155 |
| Grundy Center, IA | 5a | April 29 | October 9 | 160 |
| Guthrie Center, IA | 5a | May 2 | October 3 | 153 |
| Hale Loud Dam, MI | 5a | May 16 | October 5 | 143 |
| Hampton, IA | 5a | April 29 | October 9 | 162 |
| Hancock Experiment Farm, WI | 5a | May 10 | October 3 | 146 |
| Hanover, NH | 5a | May 1 | October 13 | 162 |
| Harrisburg, NE | 5a | May 24 | September 20 | 117 |
| Harrison, NE | 5a | May 20 | September 21 | 121 |
| Hartford, WI | 5a | May 8 | October 3 | 148 |
| Hawarden, IA | 5a | May 1 | October 4 | 155 |
| Hayden, CO | 5a | June 1 | September 20 | 109 |
| Helena, MT | 5a | May 9 | September 30 | 142 |
| Horicon, WI | 5a | May 1 | October 10 | 158 |
| Hot Springs, SD | 5a | May 16 | September 27 | 133 |
| Interior, SD | 5a | May 5 | October 7 | 152 |
| Iowa Falls, IA | 5a | April 28 | October 10 | 164 |
| Jensen, UT | 5a | May 20 | September 25 | 126 |
| Kalkaska, MI | 5a | May 24 | October 1 | 128 |
| La Crosse, WI | 5a | April 23 | October 17 | 177 |
| Lake City, MI | 5a | May 22 | September 26 | 125 |
| Lake Park, IA | 5a | April 30 | October 10 | 164 |
| Lake Wilson, MN | 5a | May 7 | September 29 | 145 |
| Lancaster, WI | 5a | April 27 | October 11 | 166 |
| Le Mars, IA | 5a | April 30 | October 4 | 157 |
| Lead, SD | 5a | May 18 | September 29 | 133 |
| Leiter, WY | 5a | May 14 | September 30 | 137 |
| Lindbergh Lake, MT | 5a | May 20 | September 22 | 120 |
| Lovell, WY | 5a | May 9 | September 29 | 142 |
| Lower St. Anthony Falls, MN | 5a | April 23 | October 16 | 175 |
| Lynch, NE | 5a | May 8 | October 2 | 147 |
| Lynxville Dam 9, WI | 5a | April 24 | October 17 | 175 |
| Madeline Island, WI | 5a | May 20 | October 9 | 140 |
| Madison, ME | 5a | May 8 | October 5 | 149 |
| Maquoketa, IA | 5a | April 25 | October 14 | 171 |
| Marquette (USW00094850), MI | 5a | May 22 | September 29 | 129 |
| Marshall, MN | 5a | May 5 | October 3 | 150 |
| Marshalltown, IA | 5a | April 28 | October 7 | 162 |
| Mason City, IA | 5a | April 29 | October 7 | 161 |
| Mason City (Airport), IA | 5a | May 3 | October 1 | 150 |
| Mauston, WI | 5a | May 2 | October 7 | 158 |
| McCall, ID | 5a | June 22 | September 2 | 72 |
| Menno, SD | 5a | May 1 | October 4 | 156 |
| Midwest, WY | 5a | May 22 | September 22 | 121 |
| Milford, IA | 5a | May 1 | October 6 | 158 |
| Minneapolis (Minneapolis/St. Paul Airport), MN | 5a | April 23 | October 18 | 176 |
| Mission, SD | 5a | May 11 | October 2 | 145 |
| Monte Vista, CO | 5a | June 11 | September 13 | 92 |
| Montello, WI | 5a | May 3 | October 5 | 153 |
| Murdo, SD | 5a | May 3 | October 9 | 158 |
| Mystic Lake, MT | 5a | June 5 | September 14 | 99 |
| New Hampton, IA | 5a | May 2 | October 5 | 155 |
| New Hope, MN | 5a | April 29 | October 12 | 163 |
| New London, WI | 5a | May 4 | October 6 | 153 |
| New Raymer, CO | 5a | May 18 | September 29 | 133 |
| Newcastle, WY | 5a | May 13 | October 3 | 143 |
| Newport, NE | 5a | May 6 | October 1 | 147 |
| Newport, NH | 5a | May 14 | October 1 | 140 |
| Northwood, IA | 5a | May 4 | October 4 | 152 |
| Nye #2, MT | 5a | June 1 | September 11 | 100 |
| Oakdale, NE | 5a | May 4 | October 4 | 153 |
| Oconto, WI | 5a | May 9 | October 6 | 150 |
| Oelrichs, SD | 5a | May 15 | September 30 | 137 |
| Onaway, MI | 5a | May 22 | October 2 | 135 |
| Osage, IA | 5a | April 30 | October 9 | 163 |
| Oshkosh, NE | 5a | May 9 | October 2 | 144 |
| Ouray, UT | 5a | May 2 | October 3 | 152 |
| Perry, IA | 5a | April 25 | October 10 | 166 |
| Peru, NY | 5a | May 4 | October 4 | 152 |
| Pierre, SD | 5a | May 6 | October 3 | 148 |
| Pinkham Notch, NH | 5a | May 18 | October 1 | 135 |
| Pocahontas, IA | 5a | April 26 | October 7 | 164 |
| Portage, WI | 5a | April 28 | October 10 | 164 |
| Powell, WY | 5a | May 19 | September 20 | 123 |
| Prairie Du Chien, WI | 5a | April 28 | October 12 | 166 |
| Primghar, IA | 5a | April 29 | October 10 | 163 |
| Rangely, CO | 5a | May 15 | October 1 | 136 |
| Rapid City (Airport), SD | 5a | May 12 | October 1 | 139 |
| Rawlins, WY | 5a | June 1 | September 15 | 105 |
| Redwood Falls, MN | 5a | April 30 | October 4 | 157 |
| Rochester, VT | 5a | May 13 | October 2 | 141 |
| Rock Rapids, IA | 5a | May 1 | October 4 | 156 |
| Rockwell City, IA | 5a | April 26 | October 10 | 167 |
| Rutland, VT | 5a | May 15 | September 27 | 132 |
| Sac City, IA | 5a | April 30 | October 6 | 158 |
| Saint James, MN | 5a | April 30 | October 7 | 160 |
| Sanborn, IA | 5a | May 1 | October 7 | 160 |
| Shawano, WI | 5a | May 9 | October 2 | 144 |
| Sioux Center, IA | 5a | April 30 | October 3 | 154 |
| Sioux Falls, SD | 5a | May 1 | October 6 | 157 |
| Sioux Rapids, IA | 5a | April 30 | October 5 | 159 |
| Spencer, IA | 5a | May 1 | October 3 | 154 |
| Springview, NE | 5a | May 10 | October 1 | 143 |
| St. Peter, MN | 5a | May 2 | October 4 | 153 |
| Stevens Point, WI | 5a | May 4 | October 7 | 155 |
| Stockton, IL | 5a | April 27 | October 9 | 165 |
| Storm Lake, IA | 5a | April 25 | October 13 | 170 |
| Superior, WI | 5a | May 6 | October 9 | 154 |
| Thermopolis, WY | 5a | May 5 | October 5 | 152 |
| Toledo, IA | 5a | April 30 | October 9 | 162 |
| Torrington, WY | 5a | May 17 | September 28 | 133 |
| Tracy, MN | 5a | May 2 | October 5 | 156 |
| Tripoli, IA | 5a | April 29 | October 9 | 162 |
| Twin Bridges, MT | 5a | June 8 | September 2 | 82 |
| Tyndall, SD | 5a | May 1 | October 7 | 158 |
| UW Arboretum - Madison, WI | 5a | May 1 | October 9 | 161 |
| Vermillion, SD | 5a | May 3 | October 3 | 153 |
| Vinton, IA | 5a | May 3 | October 3 | 151 |
| Viroqua, WI | 5a | May 7 | October 2 | 148 |
| Wakefield, NE | 5a | May 5 | October 1 | 148 |
| Waterloo, IA | 5a | April 27 | October 10 | 165 |
| Watertown, NY | 5a | May 2 | October 13 | 163 |
| Watertown (Airport), NY | 5a | May 11 | October 1 | 140 |
| Waupaca, WI | 5a | May 8 | October 6 | 151 |
| Wayne, NE | 5a | April 29 | October 11 | 163 |
| Webster City, IA | 5a | May 3 | October 2 | 150 |
| Wessington Springs, SD | 5a | May 2 | October 8 | 157 |
| West Branch, MI | 5a | May 15 | October 4 | 143 |
| West Glacier, MT | 5a | May 18 | September 20 | 124 |
| Westcliffe, CO | 5a | June 11 | September 9 | 89 |
| Wheatland, WY | 5a | May 19 | September 22 | 125 |
| White Lake, SD | 5a | May 3 | October 5 | 153 |
| Williamsburg, IA | 5a | April 28 | October 9 | 164 |
| Windom, MN | 5a | April 30 | October 10 | 162 |
| Winnebago, MN | 5a | April 27 | October 10 | 166 |
| Wisconsin Dells, WI | 5a | May 8 | October 3 | 146 |
| Worthington, MN | 5a | May 3 | October 4 | 153 |
| Yankton, SD | 5a | April 27 | October 11 | 164 |
| Yellowstone Park Mammoth, WY | 5a | June 3 | September 14 | 102 |
| near Alma, WI | 5a | April 28 | October 14 | 168 |
| near Barre, VT | 5a | May 16 | September 29 | 136 |
| near Bellevue, IA | 5a | April 25 | October 16 | 172 |
| near Boyne City, MI | 5a | May 23 | October 3 | 133 |
| near Bozeman, MT | 5a | May 26 | September 22 | 116 |
| near Colonial Pine Hills, SD | 5a | May 28 | September 18 | 112 |
| near Dillon, MT | 5a | June 5 | September 13 | 98 |
| near Four Corners, MT | 5a | May 23 | September 23 | 123 |
| near Guttenberg, IA | 5a | April 21 | October 18 | 178 |
| near Hastings, MN | 5a | April 23 | October 19 | 177 |
| near Houghton Lake, MI | 5a | May 19 | September 23 | 125 |
| near Lander, WY | 5a | May 18 | September 27 | 131 |
| near Manchester, IA | 5a | May 3 | October 4 | 154 |
| near Mapleton, IA | 5a | May 3 | October 1 | 151 |
| near Paris, ID | 5a | May 19 | September 21 | 123 |
| near Roosevelt, UT | 5a | May 23 | September 22 | 121 |
| near Roseville, MN | 5a | April 28 | October 8 | 162 |
| near Sault Ste. Marie, MI | 5a | May 9 | October 11 | 151 |
| near Scottsbluff, NE | 5a | May 5 | October 4 | 149 |
| near Sheridan, WY | 5a | May 21 | September 23 | 123 |
| near Sioux City, IA | 5a | April 29 | October 5 | 159 |
| near Sturgis, SD | 5a | May 8 | October 3 | 147 |
| near Trempealeau, WI | 5a | April 29 | October 11 | 165 |
| near Valentine, NE | 5a | May 12 | September 29 | 140 |
| near Wausau, WI | 5a | May 6 | October 4 | 150 |
| near Winona, MN | 5a | April 23 | October 21 | 180 |
Sources
- NOAA NCEI U.S. Climate Normals 1991–2020
- PRISM Group, Oregon State University — 2023 USDA Plant Hardiness Zone GIS datasets
* zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.