Danville climate

Danville Frost Dates and Growing Season

NOAA 1991-2020 normals for Danville, 2.2 km from Danville, elevation 555 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Danville. 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 21 and the first fall freeze around October 20, a growing season of about 181 days.

Median at 36°F
last May 3, first October 10
Median at 32°F
last April 21, first October 20
Median at 28°F
last April 8, first October 31

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 19May 15May 10May 6May 3Apr 30Apr 27Apr 23Apr 18
32°FMay 7May 1Apr 27Apr 24Apr 21Apr 18Apr 14Apr 11Apr 6
28°FApr 24Apr 19Apr 15Apr 11Apr 8Apr 5Apr 2Mar 31Mar 25
24°FApr 12Apr 6Apr 2Mar 31Mar 28Mar 25Mar 21Mar 16Mar 10
20°FApr 1Mar 29Mar 25Mar 21Mar 17Mar 14Mar 10Mar 5Feb 27
16°FMar 24Mar 19Mar 15Mar 11Mar 8Mar 4Feb 28Feb 24Feb 18

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 28Oct 2Oct 5Oct 8Oct 10Oct 13Oct 16Oct 18Oct 22
32°FOct 6Oct 11Oct 15Oct 18Oct 20Oct 23Oct 25Oct 29Nov 1
28°FOct 17Oct 22Oct 25Oct 28Oct 31Nov 2Nov 5Nov 8Nov 13
24°FOct 29Nov 1Nov 5Nov 7Nov 10Nov 14Nov 18Nov 22Nov 29
20°FNov 7Nov 11Nov 15Nov 20Nov 24Nov 27Dec 1Dec 3Dec 10
16°FNov 14Nov 20Nov 25Nov 29Dec 1Dec 5Dec 9Dec 14Dec 21

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°F179172167163160156152147141
32°F200194190185181177172167160
28°F226219213209205201197191184
24°F252244239234229224220215207
20°F275267261256251247242236227
16°F294285280275270264259252245

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
5,366
Cooling degree days, base 65°F
1,066
Growing degree days, base 40°F
5,992
Growing degree days, base 45°F
4,746
Growing degree days, base 50°F
3,633
Growing degree days, base 55°F
2,645
Growing degree days, base 60°F
1,784

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,16502
February93406
March714253
April35214181
May12688432
June14230666
July1314778
August3265727
September62130519
October31921216
November665146
December1,01007

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 2.2 km from Danville. 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 USC00112140 (Danville). Public domain.