Hankinson climate

Hankinson Frost Dates and Growing Season

NOAA 1991-2020 normals for Victor 4 N, 17.5 km from Hankinson, elevation 1095 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Victor 4 N. 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 4 and the first fall freeze around October 3, a growing season of about 152 days.

Median at 36°F
last May 14, first September 24
Median at 32°F
last May 4, first October 3
Median at 28°F
last April 24, first October 14

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°FMay 25May 21May 19May 16May 14May 11May 8May 6May 1
32°FMay 17May 12May 9May 6May 4May 2Apr 30Apr 26Apr 21
28°FMay 7May 3Apr 30Apr 27Apr 24Apr 22Apr 18Apr 15Apr 9
24°FApr 29Apr 24Apr 20Apr 17Apr 13Apr 10Apr 7Apr 5Apr 2
20°FApr 21Apr 16Apr 12Apr 9Apr 6Apr 4Apr 2Mar 30Mar 23
16°FApr 14Apr 9Apr 5Apr 3Mar 31Mar 29Mar 25Mar 20Mar 15

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 13Sep 17Sep 19Sep 22Sep 24Sep 26Sep 29Oct 2Oct 6
32°FSep 21Sep 26Sep 29Oct 1Oct 3Oct 6Oct 9Oct 12Oct 17
28°FSep 30Oct 3Oct 7Oct 11Oct 14Oct 17Oct 20Oct 23Oct 27
24°FOct 9Oct 15Oct 19Oct 22Oct 25Oct 27Oct 30Nov 1Nov 6
20°FOct 20Oct 26Oct 29Nov 1Nov 2Nov 4Nov 8Nov 11Nov 16
16°FOct 30Nov 1Nov 4Nov 6Nov 9Nov 12Nov 15Nov 18Nov 23

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°F149144140137133130126123116
32°F169163158155152148144140134
28°F189184179175172169163158152
24°F211204199195191187183178172
20°F226221217213209205201195188
16°F242236231227223220215211204

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
8,727
Cooling degree days, base 65°F
498
Growing degree days, base 40°F
4,173
Growing degree days, base 45°F
3,209
Growing degree days, base 50°F
2,355
Growing degree days, base 55°F
1,611
Growing degree days, base 60°F
987

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,69900
February1,42800
March1,17503
April680138
May29724237
June60111502
July16188637
August34131563
September19940307
October604367
November1,04603
December1,48900

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 17.5 km from Hankinson. 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 USC00398652 (Victor 4 N). Public domain.