McKenzie climate

McKenzie Frost Dates and Growing Season

NOAA 1991-2020 normals for Huntingdon Wtp, 16.7 km from McKenzie, elevation 440 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Huntingdon Wtp. 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 April 2 and the first fall freeze around October 31, a growing season of about 211 days.

Median at 36°F
last April 15, first October 22
Median at 32°F
last April 2, first October 31
Median at 28°F
last March 21, first November 9

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°FApr 30Apr 24Apr 21Apr 18Apr 15Apr 12Apr 8Apr 4Mar 30
32°FApr 18Apr 13Apr 9Apr 5Apr 2Mar 31Mar 26Mar 22Mar 16
28°FApr 7Apr 2Mar 29Mar 24Mar 21Mar 18Mar 14Mar 8Mar 1
24°FMar 28Mar 20Mar 16Mar 12Mar 7Mar 3Feb 28Feb 24Feb 16
20°FMar 16Mar 10Mar 4Feb 28Feb 24Feb 20Feb 14Feb 9Jan 31
16°FMar 5Feb 27Feb 22Feb 15Feb 9Feb 5Jan 31Jan 23Jan 10

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°FOct 10Oct 14Oct 17Oct 20Oct 22Oct 24Oct 26Oct 29Nov 2
32°FOct 19Oct 23Oct 25Oct 28Oct 31Nov 2Nov 4Nov 7Nov 13
28°FOct 28Nov 1Nov 3Nov 6Nov 9Nov 12Nov 16Nov 20Nov 27
24°FNov 4Nov 9Nov 13Nov 17Nov 21Nov 26Dec 1Dec 4Dec 11
20°FNov 13Nov 20Nov 27Dec 1Dec 6Dec 12Dec 18Dec 25Jan 1
16°FNov 30Dec 8Dec 17Dec 23Dec 28Jan 1Jan 5Jan 12Jan 24

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°F211204199194189186182176169
32°F234227221216211207203198191
28°F260251245239234229224218211
24°F287278272264260254249243233
20°F321308300294287280275267258
16°F351337330323315309304297285

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
96% 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
3,768
Cooling degree days, base 65°F
1,656
Growing degree days, base 40°F
7,467
Growing degree days, base 45°F
6,010
Growing degree days, base 50°F
4,698
Growing degree days, base 55°F
3,534
Growing degree days, base 60°F
2,518

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January850023
February667135
March4829127
April21743301
May56155564
June3334781
July0442907
August0406871
September27214638
October21047322
November499598
December758131

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 16.7 km from McKenzie. 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 USC00404417 (Huntingdon Wtp). Public domain.