Covington climate

Covington Frost Dates and Growing Season

NOAA 1991-2020 normals for Kent, 11.3 km from Covington, elevation 30 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Kent. 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 March 20 and the first fall freeze around November 10, a growing season of about 233 days.

Median at 36°F
last April 11, first October 27
Median at 32°F
last March 20, first November 10
Median at 28°F
last February 25, first November 24

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°FApr 30Apr 24Apr 19Apr 15Apr 11Apr 7Apr 4Mar 31Mar 26
32°FApr 8Apr 1Mar 29Mar 24Mar 20Mar 16Mar 12Mar 6Feb 27
28°FMar 16Mar 11Mar 5Feb 28Feb 25Feb 20Feb 15Feb 6Jan 19
24°FFeb 27Feb 19Feb 12Feb 1Jan 24Jan 10Jan 2Dec 20Dec 8
20°FFeb 9Jan 27Jan 13Jan 3Dec 29Dec 20Dec 12Dec 7Nov 30
16°FFeb 2Jan 21Jan 1Dec 27Dec 15Dec 9Dec 2Nov 28Nov 19

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 13Oct 17Oct 20Oct 24Oct 27Oct 29Nov 1Nov 5Nov 11
32°FOct 26Oct 31Nov 3Nov 7Nov 10Nov 13Nov 17Nov 22Nov 26
28°FNov 6Nov 11Nov 15Nov 20Nov 24Nov 27Dec 2Dec 8Dec 20
24°FNov 16Nov 24Nov 29Dec 4Dec 8Dec 16Dec 24Jan 2Jan 17
20°FNov 23Nov 30Dec 5Dec 9Dec 14Dec 25Jan 1Jan 11Jan 30
16°FNov 18Nov 26Dec 1Dec 6Dec 11Dec 22Dec 30Jan 7Jan 28

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°F217210205201197193188183175
32°F262251244239233227222216207
28°F314302291282275268261253243
24°F365355343334326317308300285
20°F365365365365365357344334323
16°F365365365365365365365365355

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
88% of years
20°F or colder
46% of years
16°F or colder
11% 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
4,369
Cooling degree days, base 65°F
285
Growing degree days, base 40°F
5,185
Growing degree days, base 45°F
3,651
Growing degree days, base 50°F
2,408
Growing degree days, base 55°F
1,459
Growing degree days, base 60°F
749

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January70505
February59606
March546030
April388194
May21610261
June10331378
July21108552
August18105552
September10529374
October3591133
November573022
December73803

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 11.3 km from Covington. 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 USC00454169 (Kent). Public domain.