Ball climate

Ball Frost Dates and Growing Season

NOAA 1991-2020 normals for Alexandria, 11.6 km from Ball, elevation 87 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Alexandria. 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 February 27 and the first fall freeze around November 27, a growing season of about 274 days.

Median at 36°F
last March 12, first November 14
Median at 32°F
last February 27, first November 27
Median at 28°F
last February 8, first December 13

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 2Mar 27Mar 20Mar 16Mar 12Mar 7Mar 3Feb 27Feb 21
32°FMar 18Mar 11Mar 6Mar 2Feb 27Feb 24Feb 19Feb 11Jan 31
28°FMar 8Mar 1Feb 24Feb 17Feb 8Feb 2Jan 29Jan 22Jan 6
24°FFeb 26Feb 12Feb 3Jan 30Jan 25Jan 19Jan 12Jan 4Dec 24
20°FFeb 5Jan 31Jan 25Jan 20Jan 14Jan 10Jan 5Dec 31Dec 21
16°F–––––––––

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 31Nov 4Nov 7Nov 11Nov 14Nov 18Nov 22Nov 27Dec 1
32°FNov 7Nov 13Nov 18Nov 22Nov 27Dec 1Dec 4Dec 8Dec 19
28°FNov 18Nov 26Dec 1Dec 6Dec 13Dec 21Dec 26Jan 1Jan 10
24°FDec 1Dec 12Dec 22Dec 28Jan 1Jan 5Jan 11Jan 18Feb 1
20°FDec 14Dec 25Dec 31Jan 2Jan 6Jan 11Jan 15Jan 22Feb 1
16°F–––––––––

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°F274265258253248242236229220
32°F306295286279274269262254243
28°F348336328317308302293284273
24°F365365365355348341334325309
20°F365365365365365365365354341
16°F365365365365365365365365365

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
96% of years
24°F or colder
73% of years
20°F or colder
36% of years
16°F or colder
9% 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
1,961
Cooling degree days, base 65°F
2,558
Growing degree days, base 40°F
9,782
Growing degree days, base 45°F
8,067
Growing degree days, base 50°F
6,468
Growing degree days, base 55°F
5,005
Growing degree days, base 60°F
3,693

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January516498
February3689139
March21636309
April75101478
May7280738
June0454904
July05471,012
August05501,015
September2393841
October63150554
November25625253
December4598126

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 11.6 km from Ball. 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 USC00160098 (Alexandria). Public domain.