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USDA Hardiness Zone 4a

Frost Dates for 56716 — Crookston, Minnesota

NOAA 1991–2020 normals from Crookston NW Exp Stn, MN (891 ft), 4 miles north.

Updated

In Crookston, the last spring frost (32°F) is around May 11 in half of years and has passed by May 25 in nine years out of ten. The first fall frost comes around September 27, as early as September 14 one year in ten, leaving a typical freeze-free season of 138 days (NOAA, Crookston NW Exp Stn, MN).

Last spring frost
May 11

50% probability

First fall frost
September 27

50% probability

Growing season
138 days

freeze-free, 50%

Hardiness zone
4a

-30 to -25°F (-34.4 to -31.7°C) coldest night

First snow
November 2

median, 1991–2020

Last snow
April 12

median, 1991–2020

Winters with snow
100%

21 of 21 observed

Snow per year
—

NOAA normal

Frost risk by date in Crookston

Half of springs at Crookston NW Exp Stn, MN see their last 32°F night by May 11; only one in ten is past it by April 28, and one in ten still has one after May 25. Planting tender crops after May 16 leaves a 30% risk of a frost on them, after May 20 20%, and after May 25 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 September 27 in half of years, as early as September 14 one year in ten, and holds off past October 10 one year in ten. A hard freeze of 28°F follows 10 days later, around October 7; in spring the one-in-ten date for 28°F is May 16, 9 days before the 32°F one. The freeze-free season lasts 138 days in a typical year, shorter than at 81% of the 142 Minnesota stations; it reaches 157 days one year in ten and falls short of 119 one year in ten. On average 186 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 11 days longer, to about May 22, and return around September 17. Severe cold of 16°F or below comes every winter, usually between November 5 and April 5.

Spring: the chance of another night this cold after the date
Low90%80%70%60%50%40%30%20%10%
36°FMay 7May 12May 16May 19May 22May 25May 28May 30Jun 3
32°FApr 28May 2May 5May 8May 11May 13May 16May 20May 25
28°FApr 18Apr 23Apr 27Apr 29May 1May 4May 7May 11May 16
24°FApr 7Apr 12Apr 16Apr 19Apr 22Apr 26Apr 29May 2May 7
20°FApr 1Apr 4Apr 6Apr 9Apr 12Apr 15Apr 18Apr 22Apr 28
16°FMar 21Mar 28Apr 1Apr 3Apr 5Apr 7Apr 10Apr 14Apr 19
Fall: the chance the first night this cold has come by the date
Low10%20%30%40%50%60%70%80%90%
36°FSep 3Sep 9Sep 12Sep 15Sep 17Sep 20Sep 22Sep 25Sep 28
32°FSep 14Sep 18Sep 22Sep 24Sep 27Sep 30Oct 3Oct 6Oct 10
28°FSep 23Sep 27Oct 1Oct 4Oct 7Oct 10Oct 14Oct 18Oct 23
24°FOct 1Oct 6Oct 10Oct 14Oct 18Oct 22Oct 25Oct 30Nov 3
20°FOct 11Oct 17Oct 22Oct 27Oct 30Nov 1Nov 3Nov 7Nov 12
16°FOct 22Oct 28Oct 31Nov 2Nov 5Nov 8Nov 11Nov 14Nov 18

Freeze probabilities 1991–2020 at Crookston NW Exp Stn, 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 56716 →Compare Crookston with another place →

Weather by month in Crookston

July is the warmest month at Crookston NW Exp Stn, MN, averaging 80°F by day and 58°F at night; January is the coldest at 16°F and -4°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 83% of years.

Warmth for growing adds up to 2,152 growing degree days a year (base 50°F), fewer than at 68% of the 142 Minnesota stations. 32% of them (699) have built up by the end of June, and July adds the most, 591. Precipitation totals 22.5 inches a year, most in June (4.2") and least in January (0.5"); May to September bring 71% of it.

Monthly normals 1991–2020 at Crookston NW Exp Stn, MN
MonthHigh °FLow °FPrecip. in32°F nightNights ≤ 32°FGDD 50°F
Jan16-40.5100%310
Feb2000.5100%280
Mar34150.7100%293
Apr51301.3100%1931
May67432.883%5208
Jun76544.20%0456
Jul80583.30%0591
Aug80553.00%0539
Sep70462.661%2272
Oct54332.1100%1551
Nov36190.8100%281
Dec2250.7100%310

Monthly normals 1991–2020 at Crookston NW Exp Stn, MN (891 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, Red Lake Falls, MN, 16 miles northeast of Crookston, has a last frost 2 days earlier (May 9), a first frost 3 days later (September 30), a season 4 days longer.

Frost dates for 56750 (Red Lake Falls) →

When it snows in Crookston, Minnesota

The first measurable snow (0.1 inch or more) in Crookston usually arrives around November 2, and the last of the season around April 12. Those are the middle dates across the winters of 1991–2020 at Crookston NW Exp Stn, MN, 4.2 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 29 days after the last snow.

Planting calendar for 56716

What to do and when, from the 50% frost dates for Crookston, Minnesota
WhenWhat to do
March 2 – March 16Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
March 16 – March 30Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
April 13 – April 27Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
May 11 onwardTransplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast.
by July 5Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops.
by September 13Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation.
September 27 onwardPlant 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 56716 is 4 miles from Crookston NW Exp Stn, MN, which stands at 891 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 56716 in zone 4a, the band where the coldest night of the year averaged -30 to -25°F (-34.4 to -31.7°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.

Other zone 4a places in Minnesota