Efland climate

Efland Frost Dates and Growing Season

NOAA 1991-2020 normals for Durham 11 W, 14 km from Efland, elevation 562 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Durham 11 W. 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 31 and the first fall freeze around November 4, a growing season of about 217 days.

Median at 36°F
last April 15, first October 26
Median at 32°F
last March 31, first November 4
Median at 28°F
last March 19, first November 15

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 6Apr 28Apr 22Apr 18Apr 15Apr 11Apr 7Apr 3Mar 30
32°FApr 19Apr 11Apr 6Apr 3Mar 31Mar 28Mar 24Mar 20Mar 14
28°FApr 5Mar 31Mar 27Mar 23Mar 19Mar 15Mar 11Mar 6Feb 28
24°FMar 24Mar 18Mar 14Mar 10Mar 6Mar 1Feb 26Feb 20Feb 9
20°FMar 14Mar 6Mar 1Feb 26Feb 20Feb 12Feb 6Jan 31Jan 20
16°FMar 3Feb 23Feb 12Feb 4Jan 31Jan 27Jan 20Jan 14Jan 5

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 14Oct 18Oct 21Oct 24Oct 26Oct 28Oct 31Nov 2Nov 5
32°FOct 22Oct 27Oct 31Nov 2Nov 4Nov 6Nov 9Nov 13Nov 18
28°FNov 3Nov 6Nov 10Nov 12Nov 15Nov 19Nov 23Nov 29Dec 4
24°FNov 12Nov 18Nov 23Nov 27Dec 1Dec 4Dec 9Dec 17Dec 28
20°FNov 25Dec 2Dec 8Dec 13Dec 21Dec 29Jan 3Jan 10Jan 19
16°FDec 9Dec 20Dec 30Jan 2Jan 8Jan 13Jan 17Jan 24Feb 2

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°F214207202198193189185178170
32°F240231225221217213208202194
28°F269260254250244239233227219
24°F306295287280275269262254245
20°F342330320312306299292284271
16°F365362350342335330320311300

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
99% of years
16°F or colder
83% 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
3,496
Cooling degree days, base 65°F
1,380
Growing degree days, base 40°F
7,300
Growing degree days, base 45°F
5,793
Growing degree days, base 50°F
4,441
Growing degree days, base 55°F
3,253
Growing degree days, base 60°F
2,231

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January769027
February612146
March4666123
April21031289
May67109507
June3265711
July0394859
August0351815
September24184610
October19837316
November460395
December687143

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 km from Efland. 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 USW00003758 (Durham 11 W). Public domain.