Shelton climate

Shelton Frost Dates and Growing Season

NOAA 1991-2020 normals for Shelton Sanderson Fld, 4 km from Shelton, elevation 271 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Shelton Sanderson Fld. 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 27 and the first fall freeze around October 16, a growing season of about 175 days.

Median at 36°F
last May 12, first October 1
Median at 32°F
last April 27, first October 16
Median at 28°F
last March 29, first November 4

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 29May 23May 19May 15May 12May 8May 5May 1Apr 28
32°FMay 12May 7May 3Apr 30Apr 27Apr 24Apr 19Apr 14Apr 6
28°FApr 25Apr 17Apr 9Apr 2Mar 29Mar 25Mar 19Mar 12Mar 3
24°FMar 26Mar 17Mar 8Mar 1Feb 25Feb 21Feb 16Feb 6Jan 16
20°FFeb 28Feb 23Feb 15Feb 7Jan 28Jan 13Jan 2Dec 17Dec 4
16°FFeb 21Feb 10Jan 28Jan 8Dec 31Dec 20Dec 12Dec 5Nov 29

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 16Sep 22Sep 26Sep 29Oct 1Oct 4Oct 7Oct 11Oct 18
32°FOct 1Oct 4Oct 6Oct 11Oct 16Oct 19Oct 25Oct 31Nov 7
28°FOct 12Oct 18Oct 24Oct 31Nov 4Nov 9Nov 15Nov 22Nov 29
24°FOct 29Nov 5Nov 12Nov 18Nov 24Nov 30Dec 7Dec 19Jan 3
20°FNov 8Nov 19Nov 28Dec 4Dec 11Dec 20Dec 30Jan 15Feb 9
16°FNov 18Nov 30Dec 4Dec 10Dec 16Dec 27Jan 6Jan 28Feb 16

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°F163156150146141137132127119
32°F200191185180175169163158150
28°F254242234226219212204197185
24°F319307295285276265256247233
20°F365360346334326317309298281
16°F365365365365365356344333317

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
99% of years
20°F or colder
84% of years
16°F or colder
48% 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
5,082
Cooling degree days, base 65°F
150
Growing degree days, base 40°F
4,410
Growing degree days, base 45°F
3,005
Growing degree days, base 50°F
1,907
Growing degree days, base 55°F
1,080
Growing degree days, base 60°F
486

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January76402
February65102
March623012
April482045
May3023178
June16516302
July5558468
August4859476
September14914316
October425089
November629014
December79002

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 km from Shelton. 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 USW00094227 (Shelton Sanderson Fld). Public domain.