McKenzie County climate

McKenzie County Frost Dates and Growing Season

NOAA 1991-2020 normals for Watford City, 10.6 km from McKenzie County, elevation 2170 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Watford City. 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 9 and the first fall freeze around September 27, a growing season of about 139 days.

Median at 36°F
last May 19, first September 20
Median at 32°F
last May 9, first September 27
Median at 28°F
last April 30, first October 7

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

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 8Sep 13Sep 16Sep 18Sep 20Sep 22Sep 24Sep 27Oct 1
32°FSep 15Sep 20Sep 22Sep 25Sep 27Sep 30Oct 2Oct 6Oct 11
28°FSep 23Sep 27Sep 30Oct 4Oct 7Oct 10Oct 13Oct 18Oct 22
24°FOct 1Oct 6Oct 11Oct 14Oct 17Oct 21Oct 24Oct 27Nov 1
20°FOct 10Oct 16Oct 21Oct 24Oct 27Oct 30Nov 2Nov 6Nov 11
16°FOct 18Oct 24Oct 28Nov 1Nov 4Nov 6Nov 10Nov 13Nov 19

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°F140133129126122118114109103
32°F159152147143139136133128122
28°F180173168163160155151147139
24°F200194189184180176171167159
20°F219212206202198194189184177
16°F237229223218214210206201193

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
8,765
Cooling degree days, base 65°F
461
Growing degree days, base 40°F
3,914
Growing degree days, base 45°F
2,971
Growing degree days, base 50°F
2,147
Growing degree days, base 55°F
1,449
Growing degree days, base 60°F
885

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,60100
February1,34000
March1,12204
April697135
May36911174
June11469408
July30187622
August50159575
September24433272
October664256
November1,08003
December1,45500

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 10.6 km from McKenzie County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00329233 (Watford City). Public domain.