Stewartsville climate

Stewartsville Frost Dates and Growing Season

NOAA 1991-2020 normals for Amity 4 Ne, 19.5 km from Stewartsville, elevation 974 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Amity 4 Ne. 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 19 and the first fall freeze around October 19, a growing season of about 180 days.

Median at 36°F
last April 30, first October 8
Median at 32°F
last April 19, first October 19
Median at 28°F
last April 8, first October 29

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

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°F178172168164160157153148140
32°F199192188184180175171166160
28°F222215210206201197193188181
24°F244237231225220216212206199
20°F263256250245240235229224217
16°F282274268264259254249244236

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
5,895
Cooling degree days, base 65°F
1,058
Growing degree days, base 40°F
5,746
Growing degree days, base 45°F
4,551
Growing degree days, base 50°F
3,484
Growing degree days, base 55°F
2,545
Growing degree days, base 60°F
1,734

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,24800
February1,00205
March762245
April4199144
May16167381
June17221654
July2340803
August6286745
September89116480
October36716189
November731035
December1,09302

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 19.5 km from Stewartsville. 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 USC00230143 (Amity 4 Ne). Public domain.