USDA Hardiness Zone 4b
Frost Dates for 55396 — Winthrop, Minnesota
NOAA 1991–2020 normals from Gaylord, MN (1,020 ft), 7 miles east.
Updated
In Winthrop, the last spring frost (32°F) is around April 24 in half of years and has passed by May 8 in nine years out of ten. The first fall frost comes around October 15, as early as September 30 one year in ten, leaving a typical freeze-free season of 170 days (NOAA, Gaylord, MN).
- Last spring frost
- April 24
- First fall frost
- October 15
- Growing season
- 170 days
- Hardiness zone
- 4b
50% probability
50% probability
freeze-free, 50%
-25 to -20°F (-31.7 to -28.9°C) coldest night
- First snow
- November 27
- Last snow
- March 25
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
26 of 26 observed
NOAA normal
Frost risk by date in Winthrop
Half of springs at Gaylord, MN see their last 32°F night by April 24; only one in ten is past it by April 9, and one in ten still has one after May 8. Planting tender crops after April 30 leaves a 30% risk of a frost on them, after May 4 20%, and after May 8 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 37% of the 142 Minnesota stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 15 in half of years, as early as September 30 one year in ten, and holds off past October 27 one year in ten. A hard freeze of 28°F follows 9 days later, around October 24; in spring the one-in-ten date for 28°F is April 29, 9 days before the 32°F one. The freeze-free season lasts 170 days in a typical year, longer than at 92% of the 142 Minnesota stations; it reaches 189 days one year in ten and falls short of 148 one year in ten. On average 161 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 10 days longer, to about May 4, and return around October 3. Severe cold of 16°F or below comes every winter, usually between November 16 and March 23.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 21 | Apr 26 | Apr 30 | May 2 | May 4 | May 7 | May 10 | May 13 | May 19 |
| 32°F | Apr 9 | Apr 14 | Apr 18 | Apr 21 | Apr 24 | Apr 28 | Apr 30 | May 4 | May 8 |
| 28°F | Apr 1 | Apr 5 | Apr 8 | Apr 11 | Apr 14 | Apr 18 | Apr 21 | Apr 24 | Apr 29 |
| 24°F | Mar 21 | Mar 29 | Apr 1 | Apr 4 | Apr 6 | Apr 9 | Apr 12 | Apr 17 | Apr 22 |
| 20°F | Mar 14 | Mar 19 | Mar 23 | Mar 28 | Mar 31 | Apr 2 | Apr 5 | Apr 8 | Apr 13 |
| 16°F | Mar 8 | Mar 13 | Mar 16 | Mar 19 | Mar 23 | Mar 27 | Mar 31 | Apr 3 | Apr 8 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 21 | Sep 26 | Sep 30 | Oct 1 | Oct 3 | Oct 6 | Oct 9 | Oct 12 | Oct 17 |
| 32°F | Sep 30 | Oct 4 | Oct 7 | Oct 11 | Oct 15 | Oct 17 | Oct 19 | Oct 23 | Oct 27 |
| 28°F | Oct 11 | Oct 16 | Oct 19 | Oct 21 | Oct 24 | Oct 27 | Oct 29 | Nov 1 | Nov 7 |
| 24°F | Oct 20 | Oct 24 | Oct 28 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 15 |
| 20°F | Oct 30 | Nov 1 | Nov 5 | Nov 7 | Nov 10 | Nov 13 | Nov 15 | Nov 18 | Nov 23 |
| 16°F | Nov 3 | Nov 7 | Nov 11 | Nov 14 | Nov 16 | Nov 19 | Nov 22 | Nov 25 | Nov 30 |
Freeze probabilities 1991–2020 at Gaylord, MN, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 55396 →Compare Winthrop with another place →
Weather by month in Winthrop
July is the warmest month at Gaylord, MN, averaging 82°F by day and 63°F at night; January is the coldest at 21°F and 6°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 28% of years.
Warmth for growing adds up to 2,710 growing degree days a year (base 50°F), more than at 84% of the 142 Minnesota stations. 34% of them (918) have built up by the end of June, and July adds the most, 704.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 21 | 6 | 100% | 31 | 0 |
| Feb | 26 | 9 | 100% | 27 | 0 |
| Mar | 38 | 22 | 100% | 26 | 7 |
| Apr | 54 | 35 | 99% | 12 | 60 |
| May | 68 | 48 | 28% | 1 | 285 |
| Jun | 78 | 59 | 0% | 0 | 567 |
| Jul | 82 | 63 | 0% | 0 | 704 |
| Aug | 80 | 60 | 0% | 0 | 623 |
| Sep | 72 | 51 | 11% | <1 | 365 |
| Oct | 57 | 38 | 96% | 9 | 92 |
| Nov | 41 | 25 | 100% | 24 | 8 |
| Dec | 27 | 13 | 100% | 30 | 0 |
Monthly normals 1991–2020 at Gaylord, MN (1,020 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Brownton Wwtp, MN, 14 miles north of Winthrop, has a last frost 6 days later (April 30), a first frost 11 days earlier (October 4), a season 14 days shorter.
When it snows in Winthrop, Minnesota
The first measurable snow (0.1 inch or more) in Winthrop usually arrives around November 27, and the last of the season around March 25. Those are the middle dates across the winters of 1991–2020 at Gaylord, MN, 7.4 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 30 days after the last snow.
Planting calendar for 55396
| When | What to do |
|---|---|
| February 13 – February 27 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 27 – March 13 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 27 – April 10 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 24 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 23 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 1 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 15 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 55396 is 7 miles from Gaylord, MN, which stands at 1,020 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 55307 (Arlington). The 2023 USDA Plant Hardiness Zone Map lists ZIP 55396 in zone 4b, the band where the coldest night of the year averaged -25 to -20°F (-31.7 to -28.9°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across Minnesota →
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.