Johnson climate

Johnson Frost Dates and Growing Season

NOAA 1991-2020 normals for Fayetteville Exp Stn, 3.6 km from Johnson, elevation 1270 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Fayetteville Exp Stn. 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 4 and the first fall freeze around October 31, a growing season of about 209 days.

Median at 36°F
last April 16, first October 22
Median at 32°F
last April 4, first October 31
Median at 28°F
last March 24, 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°FMay 2Apr 28Apr 24Apr 20Apr 16Apr 12Apr 9Apr 5Mar 31
32°FApr 22Apr 16Apr 11Apr 7Apr 4Apr 1Mar 29Mar 24Mar 18
28°FApr 9Apr 4Mar 31Mar 29Mar 24Mar 20Mar 16Mar 11Mar 4
24°FMar 31Mar 24Mar 18Mar 14Mar 10Mar 7Mar 3Feb 28Feb 21
20°FMar 17Mar 11Mar 7Mar 3Mar 1Feb 26Feb 21Feb 16Feb 9
16°FMar 10Mar 4Mar 1Feb 25Feb 19Feb 14Feb 9Jan 31Jan 23

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

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°F208202197193188183178172165
32°F233225219213209205201196188
28°F258248242237232227222216209
24°F280272265260255249244238228
20°F305295288282277271265259250
16°F333321313306301296289281270

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
3,940
Cooling degree days, base 65°F
1,536
Growing degree days, base 40°F
7,225
Growing degree days, base 45°F
5,793
Growing degree days, base 50°F
4,504
Growing degree days, base 55°F
3,361
Growing degree days, base 60°F
2,371

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January877015
February684031
March5176113
April23730277
May80112500
June5299744
July0436900
August1409872
September33201619
October21541314
November508396
December784023

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 3.6 km from Johnson. 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 USC00032444 (Fayetteville Exp Stn). Public domain.