Gainesville climate

Gainesville Frost Dates and Growing Season

NOAA 1991-2020 normals for Washington Dc Dulles AP, 20.7 km from Gainesville, elevation 290 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Washington Dc Dulles AP. 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 15 and the first fall freeze around October 24, a growing season of about 194 days.

Median at 36°F
last April 29, first October 14
Median at 32°F
last April 15, first October 24
Median at 28°F
last April 1, first November 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°FMay 17May 11May 6May 2Apr 29Apr 26Apr 22Apr 18Apr 12
32°FApr 30Apr 25Apr 21Apr 18Apr 15Apr 11Apr 7Apr 4Mar 31
28°FApr 16Apr 10Apr 6Apr 3Apr 1Mar 29Mar 26Mar 23Mar 18
24°FApr 3Mar 31Mar 28Mar 24Mar 20Mar 17Mar 13Mar 8Mar 3
20°FMar 25Mar 19Mar 15Mar 11Mar 7Mar 4Feb 28Feb 25Feb 18
16°FMar 15Mar 9Mar 4Feb 28Feb 24Feb 20Feb 14Feb 8Jan 31

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 6Oct 10Oct 12Oct 14Oct 17Oct 20Oct 23Oct 27
32°FOct 10Oct 14Oct 18Oct 21Oct 24Oct 27Oct 30Nov 1Nov 5
28°FOct 21Oct 27Oct 31Nov 1Nov 4Nov 7Nov 10Nov 14Nov 19
24°FNov 3Nov 7Nov 11Nov 14Nov 17Nov 20Nov 25Nov 30Dec 5
20°FNov 13Nov 19Nov 25Nov 29Dec 2Dec 6Dec 10Dec 17Dec 25
16°FNov 28Dec 3Dec 9Dec 16Dec 22Dec 26Dec 31Jan 5Jan 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°F189183178174170166160156148
32°F214207202198194189184178170
28°F240230226222218214210205197
24°F267259253248243239234229223
20°F297288282276270266260253245
16°F326317309304298292285278269

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
4,604
Cooling degree days, base 65°F
1,233
Growing degree days, base 40°F
6,404
Growing degree days, base 45°F
5,066
Growing degree days, base 50°F
3,886
Growing degree days, base 55°F
2,856
Growing degree days, base 60°F
1,972

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January96409
February801011
March647254
April32020197
May11584436
June13238675
July0378843
August1334798
September45153558
October28422232
November570158
December845015

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 20.7 km from Gainesville. 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 USW00093738 (Washington Dc Dulles AP). Public domain.