Kopperston climate

Kopperston Frost Dates and Growing Season

NOAA 1991-2020 normals for Oceana 2 Se, 9.2 km from Kopperston, elevation 1320 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Oceana 2 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 22 and the first fall freeze around October 24, a growing season of about 184 days.

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

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 17Oct 20Oct 23Oct 26
32°FOct 12Oct 16Oct 19Oct 21Oct 24Oct 26Oct 28Nov 1Nov 4
28°FOct 20Oct 24Oct 27Oct 30Nov 1Nov 4Nov 6Nov 10Nov 15
24°FOct 31Nov 3Nov 6Nov 9Nov 11Nov 14Nov 18Nov 22Nov 29
20°FNov 8Nov 12Nov 16Nov 20Nov 25Nov 28Dec 1Dec 6Dec 15
16°FNov 15Nov 24Nov 29Dec 2Dec 6Dec 13Dec 19Dec 24Jan 1

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°F184177172169165161157151144
32°F203197192188184180176171162
28°F229221216211206202197193186
24°F252244239234230225220214206
20°F281271264258253248243236230
16°F312302294288282276271262254

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
4,889
Cooling degree days, base 65°F
880
Growing degree days, base 40°F
5,902
Growing degree days, base 45°F
4,598
Growing degree days, base 50°F
3,451
Growing degree days, base 55°F
2,449
Growing degree days, base 60°F
1,590

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,01005
February81509
March670146
April34210183
May13963396
June18171603
July2268732
August2241704
September52112511
October31015215
November633038
December89709

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 9.2 km from Kopperston. 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 USC00466600 (Oceana 2 Se). Public domain.