Hollymead climate

Hollymead Frost Dates and Growing Season

NOAA 1991-2020 normals for Charlottesville AP, 2.6 km from Hollymead, elevation 641 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Charlottesville 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 3 and the first fall freeze around November 1, a growing season of about 211 days.

Median at 36°F
last April 19, first October 23
Median at 32°F
last April 3, first November 1
Median at 28°F
last March 21, first November 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°FMay 9May 2Apr 27Apr 23Apr 19Apr 16Apr 12Apr 7Apr 2
32°FApr 23Apr 15Apr 10Apr 6Apr 3Apr 1Mar 28Mar 25Mar 19
28°FApr 5Apr 1Mar 28Mar 24Mar 21Mar 18Mar 15Mar 10Mar 3
24°FMar 24Mar 20Mar 16Mar 14Mar 9Mar 5Mar 2Feb 25Feb 16
20°FMar 17Mar 10Mar 4Feb 28Feb 24Feb 18Feb 12Feb 6Jan 30
16°FMar 6Feb 25Feb 18Feb 11Feb 6Feb 1Jan 28Jan 20Jan 11

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 10Oct 14Oct 17Oct 20Oct 23Oct 26Oct 29Nov 1Nov 4
32°FOct 19Oct 24Oct 27Oct 31Nov 1Nov 4Nov 7Nov 11Nov 16
28°FOct 29Nov 2Nov 6Nov 10Nov 13Nov 16Nov 20Nov 25Dec 2
24°FNov 10Nov 15Nov 21Nov 25Nov 30Dec 3Dec 7Dec 13Dec 21
20°FNov 25Dec 1Dec 6Dec 11Dec 17Dec 22Dec 26Jan 3Jan 11
16°FDec 11Dec 20Dec 25Dec 30Jan 2Jan 7Jan 13Jan 18Jan 28

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°F206200195190185181176170163
32°F233225220215211207202196189
28°F263254248243238233229222215
24°F295285277271267261255249240
20°F325315307301295288282274265
16°F353342334329323317310303293

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
93% 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
3,767
Cooling degree days, base 65°F
1,497
Growing degree days, base 40°F
7,227
Growing degree days, base 45°F
5,758
Growing degree days, base 50°F
4,455
Growing degree days, base 55°F
3,311
Growing degree days, base 60°F
2,324

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January825020
February663131
March5125103
April23438276
May76124514
June5299744
July0434899
August1370834
September28189611
October21436303
November479291
December731129

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 2.6 km from Hollymead. 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 USW00093736 (Charlottesville AP). Public domain.