Wishek climate

Wishek Frost Dates and Growing Season

NOAA 1991-2020 normals for Wishek, 0.5 km from Wishek, elevation 2037 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Wishek. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around May 13 and the first fall freeze around September 27, a growing season of about 135 days.

Median at 36°F
last May 23, first September 19
Median at 32°F
last May 13, first September 27
Median at 28°F
last May 3, first October 5

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°FJun 6Jun 1May 29May 26May 23May 21May 18May 15May 11
32°FMay 28May 22May 18May 16May 13May 11May 8May 5May 2
28°FMay 17May 12May 8May 6May 3May 1Apr 29Apr 25Apr 19
24°FMay 8May 3May 1Apr 28Apr 24Apr 20Apr 17Apr 14Apr 10
20°FApr 30Apr 24Apr 20Apr 17Apr 14Apr 11Apr 8Apr 5Apr 1
16°FApr 21Apr 15Apr 12Apr 8Apr 6Apr 3Apr 1Mar 28Mar 21

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°FSep 5Sep 9Sep 13Sep 16Sep 19Sep 21Sep 23Sep 26Sep 30
32°FSep 15Sep 20Sep 23Sep 25Sep 27Sep 29Oct 1Oct 5Oct 10
28°FSep 23Sep 28Sep 30Oct 3Oct 5Oct 8Oct 12Oct 16Oct 20
24°FOct 1Oct 5Oct 10Oct 13Oct 16Oct 18Oct 22Oct 24Oct 29
20°FOct 10Oct 16Oct 19Oct 23Oct 26Oct 29Nov 1Nov 4Nov 7
16°FOct 20Oct 26Oct 30Nov 1Nov 3Nov 6Nov 8Nov 11Nov 16

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F13412812412011611310910597
32°F152146142139135131127123116
28°F173166162157154151146141134
24°F192185181177173169164159152
20°F211205200196192189184179171
16°F229221217213210206202197190

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
100% of years
24°F or colder
100% of years
20°F or colder
100% of years
16°F or colder
100% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
9,017
Cooling degree days, base 65°F
371
Growing degree days, base 40°F
3,785
Growing degree days, base 45°F
2,860
Growing degree days, base 50°F
2,046
Growing degree days, base 55°F
1,347
Growing degree days, base 60°F
784

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,66500
February1,40500
March1,18102
April729030
May36311178
June11357397
July34155586
August52115529
September23932271
October655153
November1,09702
December1,48500

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 0.5 km from Wishek. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00329515 (Wishek). Public domain.