Parsons climate

Parsons Frost Dates and Growing Season

NOAA 1991-2020 normals for Parsons 3 Se, 4.8 km from Parsons, elevation 1775 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Parsons 3 Se. 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 24 and the first fall freeze around October 24, a growing season of about 182 days.

Median at 36°F
last May 4, first October 15
Median at 32°F
last April 24, first October 24
Median at 28°F
last April 10, 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 21May 16May 12May 7May 4May 1Apr 28Apr 25Apr 20
32°FMay 11May 4Apr 30Apr 27Apr 24Apr 21Apr 18Apr 14Apr 8
28°FApr 30Apr 22Apr 18Apr 14Apr 10Apr 7Apr 3Mar 31Mar 26
24°FApr 13Apr 7Apr 4Apr 1Mar 30Mar 26Mar 22Mar 18Mar 12
20°FApr 3Mar 29Mar 24Mar 20Mar 17Mar 14Mar 9Mar 5Feb 28
16°FMar 25Mar 19Mar 14Mar 10Mar 7Mar 3Feb 28Feb 23Feb 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°FOct 4Oct 8Oct 11Oct 13Oct 15Oct 18Oct 21Oct 23Oct 27
32°FOct 11Oct 15Oct 19Oct 22Oct 24Oct 27Oct 30Nov 1Nov 5
28°FOct 20Oct 25Oct 28Oct 31Nov 1Nov 4Nov 7Nov 11Nov 16
24°FOct 30Nov 2Nov 6Nov 9Nov 12Nov 15Nov 18Nov 23Dec 1
20°FNov 7Nov 12Nov 15Nov 20Nov 24Nov 29Dec 1Dec 6Dec 16
16°FNov 16Nov 24Nov 29Dec 2Dec 7Dec 12Dec 18Dec 23Dec 30

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°F181175170165162158153149143
32°F203195190186182178173167160
28°F226220214210206202197191183
24°F253244237232228224220214207
20°F280270262256252246242235227
16°F304294287280274269264256246

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
5,308
Cooling degree days, base 65°F
782
Growing degree days, base 40°F
5,598
Growing degree days, base 45°F
4,334
Growing degree days, base 50°F
3,223
Growing degree days, base 55°F
2,262
Growing degree days, base 60°F
1,444

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,06206
February88308
March740039
April4018153
May16957364
June32149567
July3248710
August5219679
September7489466
October35112182
November660039
December929011

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 4.8 km from Parsons. 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 USC00466867 (Parsons 3 Se). Public domain.