Macon County climate

Macon County Frost Dates and Growing Season

NOAA 1991-2020 normals for Long Branch Rsvr, 10.2 km from Macon County, elevation 820 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Long Branch Rsvr. 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 8 and the first fall freeze around October 28, a growing season of about 201 days.

Median at 36°F
last April 22, first October 18
Median at 32°F
last April 8, first October 28
Median at 28°F
last March 29, first November 5

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 5May 1Apr 28Apr 25Apr 22Apr 19Apr 15Apr 11Apr 5
32°FApr 24Apr 19Apr 14Apr 11Apr 8Apr 5Apr 2Mar 30Mar 23
28°FApr 12Apr 7Apr 3Mar 31Mar 29Mar 25Mar 21Mar 16Mar 9
24°FApr 2Mar 29Mar 24Mar 20Mar 17Mar 14Mar 10Mar 6Mar 2
20°FMar 27Mar 19Mar 15Mar 11Mar 9Mar 6Mar 3Feb 28Feb 22
16°FMar 16Mar 11Mar 8Mar 5Mar 2Feb 28Feb 24Feb 19Feb 12

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

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°F198192187183178174170165159
32°F221214208205201197193188180
28°F243236230225220216212207199
24°F266258251246241237232226218
20°F285277270264260255249243235
16°F300292287282276272266259251

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
5,306
Cooling degree days, base 65°F
1,308
Growing degree days, base 40°F
6,302
Growing degree days, base 45°F
5,046
Growing degree days, base 50°F
3,921
Growing degree days, base 55°F
2,924
Growing degree days, base 60°F
2,048

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,17502
February92307
March687361
April35217186
May11698450
June10268708
July1397862
August2344807
September59152544
October30327238
November660151
December1,02006

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 10.2 km from Macon County. 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 USC00235050 (Long Branch Rsvr). Public domain.