Mar-Mac climate

Mar-Mac Frost Dates and Growing Season

NOAA 1991-2020 normals for Goldsboro 4 Se, 8.3 km from Mar-Mac, elevation 109 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Goldsboro 4 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 March 15 and the first fall freeze around November 18, a growing season of about 250 days.

Median at 36°F
last March 29, first November 6
Median at 32°F
last March 15, first November 18
Median at 28°F
last February 28, first December 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°FApr 12Apr 6Apr 3Mar 31Mar 29Mar 25Mar 21Mar 16Mar 9
32°FApr 1Mar 28Mar 23Mar 19Mar 15Mar 11Mar 6Mar 1Feb 23
28°FMar 20Mar 12Mar 6Mar 3Feb 28Feb 24Feb 20Feb 12Feb 4
24°FMar 7Feb 28Feb 23Feb 17Feb 10Feb 4Jan 31Jan 25Jan 13
20°FFeb 24Feb 13Feb 4Jan 31Jan 29Jan 24Jan 17Jan 12Jan 2
16°FFeb 10Feb 1Jan 30Jan 27Jan 23Jan 17Jan 13Jan 8Jan 1

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 25Oct 30Nov 1Nov 4Nov 6Nov 10Nov 12Nov 17Nov 23
32°FNov 2Nov 7Nov 11Nov 14Nov 18Nov 22Nov 26Dec 1Dec 7
28°FNov 14Nov 20Nov 26Dec 1Dec 4Dec 8Dec 14Dec 22Jan 1
24°FNov 28Dec 6Dec 11Dec 19Dec 26Dec 31Jan 4Jan 11Jan 20
20°FDec 12Dec 23Dec 29Jan 2Jan 7Jan 13Jan 17Jan 23Feb 1
16°FDec 28Jan 3Jan 7Jan 12Jan 16Jan 21Jan 25Jan 29Feb 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°F249239233228224219215210204
32°F278267261255250244239234227
28°F312302295288282275268261251
24°F344334326319313307302294280
20°F365365359348342335330320309
16°F365365365365365363351342333

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
97% of years
20°F or colder
77% of years
16°F or colder
41% 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
2,657
Cooling degree days, base 65°F
2,082
Growing degree days, base 40°F
8,684
Growing degree days, base 45°F
7,050
Growing degree days, base 50°F
5,559
Growing degree days, base 55°F
4,230
Growing degree days, base 60°F
3,071

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January641353
February499265
March35416190
April13275400
May31206640
June1402852
July0507972
August0463928
September7302745
October10787448
November33214189
December553578

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 8.3 km from Mar-Mac. 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 USW00013713 (Goldsboro 4 Se). Public domain.