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USDA Hardiness Zone 4a

Frost Dates for 58701 — Minot, North Dakota

NOAA 1991–2020 normals from Minot Exp Stn, ND (1,769 ft), 1 miles south.

Updated

In Minot, the last spring frost (32°F) is around May 13 in half of years and has passed by May 26 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 136 days (NOAA, Minot Exp Stn, ND).

Last spring frost
May 13

50% probability

First fall frost
September 27

50% probability

Growing season
136 days

freeze-free, 50%

Hardiness zone
4a

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

First snow
October 24

median, 1991–2020

Last snow
April 16

median, 1991–2020

Winters with snow
100%

22 of 22 observed

Snow per year
51.8"

NOAA normal

Frost risk by date in Minot

Half of springs at Minot Exp Stn, ND see their last 32°F night by May 13; only one in ten is past it by May 1, and one in ten still has one after May 26. Planting tender crops after May 18 leaves a 30% risk of a frost on them, after May 21 20%, and after May 26 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 21% of the 33 North Dakota 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 9 one year in ten. A hard freeze of 28°F follows 8 days later, around October 5; in spring the one-in-ten date for 28°F is May 16, 10 days before the 32°F one. The freeze-free season lasts 136 days in a typical year, shorter than at 52% of the 33 North Dakota stations; it reaches 153 days one year in ten and falls short of 118 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 9 days longer, to about May 22, and return around September 20. Severe cold of 16°F or below comes every winter, usually between October 31 and April 6.

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

Freeze probabilities 1991–2020 at Minot Exp Stn, ND, 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 58701 →Compare Minot with another place →

Weather by month in Minot

July is the warmest month at Minot Exp Stn, ND, averaging 80°F by day and 57°F at night; January is the coldest at 19°F and 1°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month.

Warmth for growing adds up to 1,978 growing degree days a year (base 50°F), fewer than at 76% of the 33 North Dakota stations. 30% of them (598) have built up by the end of June, and July adds the most, 561. Precipitation totals 19.2 inches a year, most in June (3.7") and least in January (0.6"); May to September bring 67% of it.

Monthly normals 1991–2020 at Minot Exp Stn, ND
MonthHigh °FLow °FPrecip. in32°F nightNights ≤ 32°FGDD 50°F
Jan1910.6100%310
Feb2240.6100%280
Mar35160.8100%291
Apr51291.2100%1927
May65412.891%4174
Jun74523.73%<1396
Jul80572.50%0561
Aug80542.10%0526
Sep70451.764%1246
Oct53321.4100%1644
Nov36181.0100%283
Dec2360.8100%310

Monthly normals 1991–2020 at Minot Exp Stn, ND (1,769 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, Minot International Airport, ND, 4 miles north of Minot, has a last frost 3 days earlier (May 10), a first frost 4 days later (October 1), a season 8 days longer.

Frost dates for 58703 (Minot) →

When it snows in Minot, North Dakota

The first measurable snow (0.1 inch or more) in Minot usually arrives around October 24, and the last of the season around April 16. Those are the middle dates across the winters of 1991–2020 at Minot Exp Stn, ND, 1.4 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 27 days after the last snow.

Planting calendar for 58701

What to do and when, from the 50% frost dates for Minot, North Dakota
WhenWhat to do
March 4 – March 18Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
March 18 – April 1Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
April 15 – April 29Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
May 13 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 58701 is 1 mile from Minot Exp Stn, ND, which stands at 1,769 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 58701 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 North Dakota →

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 North Dakota