Bottineau climate

Bottineau Frost Dates and Growing Season

NOAA 1991-2020 normals for Bottineau, 0.8 km from Bottineau, elevation 1619 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bottineau. 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 15 and the first fall freeze around September 25, a growing season of about 133 days.

Median at 36°F
last May 25, first September 18
Median at 32°F
last May 15, first September 25
Median at 28°F
last May 6, first October 2

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

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 7Sep 10Sep 13Sep 16Sep 18Sep 20Sep 23Sep 25Sep 29
32°FSep 13Sep 18Sep 21Sep 23Sep 25Sep 28Sep 30Oct 3Oct 7
28°FSep 21Sep 25Sep 28Sep 30Oct 2Oct 5Oct 8Oct 11Oct 16
24°FSep 29Oct 2Oct 5Oct 8Oct 11Oct 14Oct 17Oct 20Oct 24
20°FOct 5Oct 10Oct 14Oct 17Oct 19Oct 22Oct 25Oct 28Nov 1
16°FOct 14Oct 18Oct 22Oct 25Oct 28Nov 1Nov 3Nov 7Nov 12

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°F13412812412011611210910498
32°F150144140136133130127122114
28°F168162157153150146142138132
24°F187180174170166163159154147
20°F205199194189185180176171164
16°F223216211207203198194188180

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
9,917
Cooling degree days, base 65°F
319
Growing degree days, base 40°F
3,584
Growing degree days, base 45°F
2,697
Growing degree days, base 50°F
1,911
Growing degree days, base 55°F
1,243
Growing degree days, base 60°F
704

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,84100
February1,54800
March1,29302
April758024
May37910168
June12154386
July40124549
August60104510
September27526236
October736136
November1,20301
December1,66300

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 0.8 km from Bottineau. 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 USC00320941 (Bottineau). Public domain.