Clifton Forge climate

Clifton Forge Frost Dates and Growing Season

NOAA 1991-2020 normals for Covington Fltr Plt, 14.4 km from Clifton Forge, elevation 1244 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Covington Fltr Plt. 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 18, a growing season of about 172 days.

Median at 36°F
last May 8, first October 8
Median at 32°F
last April 27, first October 18
Median at 28°F
last April 14, first October 28

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 26May 21May 16May 12May 8May 5May 2Apr 28Apr 22
32°FMay 15May 9May 4May 1Apr 27Apr 23Apr 20Apr 16Apr 12
28°FMay 2Apr 24Apr 20Apr 16Apr 14Apr 9Apr 6Apr 2Mar 30
24°FApr 14Apr 8Apr 4Apr 1Mar 30Mar 26Mar 22Mar 17Mar 11
20°FApr 2Mar 28Mar 23Mar 19Mar 16Mar 12Mar 8Mar 4Feb 26
16°FMar 21Mar 16Mar 11Mar 6Mar 1Feb 27Feb 22Feb 14Feb 6

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 25Sep 30Oct 3Oct 6Oct 8Oct 11Oct 14Oct 18Oct 23
32°FOct 4Oct 8Oct 12Oct 14Oct 18Oct 21Oct 24Oct 28Nov 1
28°FOct 13Oct 18Oct 23Oct 26Oct 28Nov 1Nov 2Nov 5Nov 10
24°FOct 25Oct 29Nov 1Nov 4Nov 6Nov 9Nov 13Nov 17Nov 24
20°FNov 2Nov 8Nov 12Nov 15Nov 19Nov 23Nov 28Dec 2Dec 8
16°FNov 14Nov 20Nov 27Dec 1Dec 5Dec 10Dec 16Dec 22Jan 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°F172166160155150146142136131
32°F195187181177172168162157149
28°F219211205200197193187180172
24°F247238231226222217213207200
20°F278268261255249244238231224
16°F310299292285279274267260251

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
5,144
Cooling degree days, base 65°F
704
Growing degree days, base 40°F
5,505
Growing degree days, base 45°F
4,237
Growing degree days, base 50°F
3,124
Growing degree days, base 55°F
2,162
Growing degree days, base 60°F
1,355

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,02304
February84604
March708033
April3845146
May16341351
June29137558
July3234696
August7201659
September7677453
October3399181
November659032
December90707

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 14.4 km from Clifton Forge. 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 USC00442044 (Covington Fltr Plt). Public domain.