Wellston climate

Wellston Frost Dates and Growing Season

NOAA 1991-2020 normals for Jackson 3 Nw, 15.7 km from Wellston, elevation 845 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Jackson 3 Nw. 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 22 and the first fall freeze around October 21, a growing season of about 181 days.

Median at 36°F
last May 4, first October 12
Median at 32°F
last April 22, first October 21
Median at 28°F
last April 9, first November 1

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 22May 16May 11May 8May 4May 1Apr 29Apr 23Apr 18
32°FMay 11May 6Apr 30Apr 26Apr 22Apr 19Apr 17Apr 13Apr 7
28°FApr 26Apr 20Apr 16Apr 13Apr 9Apr 6Apr 4Apr 1Mar 25
24°FApr 11Apr 6Apr 3Mar 31Mar 29Mar 26Mar 22Mar 18Mar 12
20°FMar 31Mar 28Mar 23Mar 19Mar 16Mar 13Mar 9Mar 5Feb 28
16°FMar 22Mar 18Mar 14Mar 10Mar 6Mar 2Feb 28Feb 22Feb 14

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

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°F179172167163160156152147139
32°F201194189185181177173167159
28°F226219213209205201197192185
24°F253244238233228224220216209
20°F278267261256252247243236229
16°F301294288282276271265259250

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
5,565
Cooling degree days, base 65°F
676
Growing degree days, base 40°F
5,366
Growing degree days, base 45°F
4,138
Growing degree days, base 50°F
3,055
Growing degree days, base 55°F
2,111
Growing degree days, base 60°F
1,311

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,11906
February93006
March757244
April39311159
May17946343
June32133551
July5221680
August10185640
September9471430
October3868156
November689032
December97209

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 15.7 km from Wellston. 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 USC00334004 (Jackson 3 Nw). Public domain.