Athens climate

Athens Frost Dates and Growing Season

NOAA 1991-2020 normals for Waverly, 5 km from Athens, elevation 845 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Waverly. 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 6 and the first fall freeze around October 10, a growing season of about 157 days.

Median at 36°F
last May 18, first October 1
Median at 32°F
last May 6, first October 10
Median at 28°F
last April 23, first October 25

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 31May 28May 25May 22May 18May 15May 11May 7May 1
32°FMay 22May 16May 12May 9May 6May 2Apr 30Apr 26Apr 22
28°FMay 10May 4Apr 30Apr 27Apr 23Apr 20Apr 18Apr 13Apr 8
24°FApr 23Apr 19Apr 16Apr 12Apr 9Apr 6Apr 4Apr 1Mar 29
20°FApr 13Apr 8Apr 5Apr 3Apr 1Mar 31Mar 28Mar 24Mar 18
16°FApr 4Apr 1Mar 30Mar 26Mar 23Mar 21Mar 18Mar 14Mar 10

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 18Sep 23Sep 26Sep 29Oct 1Oct 2Oct 5Oct 8Oct 13
32°FSep 27Oct 1Oct 4Oct 6Oct 10Oct 13Oct 17Oct 21Oct 26
28°FOct 6Oct 12Oct 18Oct 21Oct 25Oct 29Nov 1Nov 2Nov 6
24°FOct 21Oct 27Oct 31Nov 1Nov 4Nov 6Nov 10Nov 13Nov 18
20°FNov 1Nov 5Nov 10Nov 12Nov 15Nov 18Nov 21Nov 25Dec 1
16°FNov 11Nov 16Nov 20Nov 23Nov 27Nov 30Dec 3Dec 8Dec 16

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°F156148143139135131127122115
32°F177170166161157152147142135
28°F203196191187182178172166158
24°F227220216211208203199194187
20°F250243237233230226221216210
16°F272264258254249245240234227

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
6,541
Cooling degree days, base 65°F
559
Growing degree days, base 40°F
4,678
Growing degree days, base 45°F
3,571
Growing degree days, base 50°F
2,609
Growing degree days, base 55°F
1,784
Growing degree days, base 60°F
1,097

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,23201
February1,06701
March945010
April562367
May25332267
June59115506
July11193648
August19159604
September13453374
October4524112
November752017
December1,05402

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 5 km from Athens. 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 USC00309047 (Waverly). Public domain.