Athena climate

Athena Frost Dates and Growing Season

NOAA 1991-2020 normals for Pendleton Branch Exp Stn, 14.7 km from Athena, elevation 1487 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Pendleton Branch Exp Stn. 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 May 12 and the first fall freeze around September 27, a growing season of about 135 days.

Median at 36°F
last June 5, first September 9
Median at 32°F
last May 12, first September 27
Median at 28°F
last April 27, first October 10

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°FJun 25Jun 18Jun 13Jun 9Jun 5May 31May 28May 23May 17
32°FJun 2May 25May 19May 15May 12May 9May 5May 2Apr 28
28°FMay 11May 7May 3Apr 30Apr 27Apr 24Apr 20Apr 14Apr 6
24°FApr 30Apr 23Apr 17Apr 11Apr 5Mar 31Mar 26Mar 18Mar 8
20°FApr 7Mar 28Mar 19Mar 12Mar 7Mar 1Feb 25Feb 18Feb 7
16°FMar 10Mar 2Feb 26Feb 22Feb 16Feb 7Jan 27Jan 13Jan 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°FAug 25Sep 1Sep 4Sep 7Sep 9Sep 13Sep 18Sep 22Sep 27
32°FSep 8Sep 13Sep 18Sep 23Sep 27Sep 30Oct 3Oct 6Oct 12
28°FSep 24Oct 1Oct 4Oct 7Oct 10Oct 14Oct 18Oct 22Oct 28
24°FOct 7Oct 14Oct 18Oct 22Oct 26Oct 29Nov 2Nov 8Nov 20
20°FOct 19Oct 26Oct 31Nov 5Nov 11Nov 17Nov 25Dec 3Dec 13
16°FOct 30Nov 7Nov 16Nov 24Dec 1Dec 5Dec 11Dec 19Jan 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°F1251151091039792878071
32°F158151146141135129124117107
28°F197187180174168162158152145
24°F242228220212205199192184173
20°F291276267258249241232224212
16°F333319307298289279271261249

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
98% 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
5,679
Cooling degree days, base 65°F
454
Growing degree days, base 40°F
4,611
Growing degree days, base 45°F
3,346
Growing degree days, base 50°F
2,325
Growing degree days, base 55°F
1,513
Growing degree days, base 60°F
893

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January93902
February76903
March677015
April494054
May29111204
June12945367
July20197641
August32165598
September15636334
October469192
November743012
December96102

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 14.7 km from Athena. 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 USC00356540 (Pendleton Branch Exp Stn). Public domain.