Christiansburg climate

Christiansburg Frost Dates and Growing Season

NOAA 1991-2020 normals for Christiansburg, 0.6 km from Christiansburg, elevation 2100 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Christiansburg. 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 19 and the first fall freeze around October 23, a growing season of about 186 days.

Median at 36°F
last May 3, first October 12
Median at 32°F
last April 19, first October 23
Median at 28°F
last April 5, first November 1

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

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 1Oct 5Oct 8Oct 10Oct 12Oct 15Oct 17Oct 21Oct 26
32°FOct 10Oct 13Oct 17Oct 20Oct 23Oct 26Oct 29Nov 1Nov 4
28°FOct 20Oct 25Oct 28Oct 30Nov 1Nov 4Nov 7Nov 10Nov 16
24°FOct 30Nov 3Nov 6Nov 9Nov 12Nov 15Nov 19Nov 25Dec 3
20°FNov 7Nov 13Nov 17Nov 22Nov 27Dec 1Dec 5Dec 11Dec 22
16°FNov 19Nov 28Dec 2Dec 7Dec 13Dec 20Dec 25Jan 1Jan 9

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°F183177171166163159154149141
32°F207199195190186181177171163
28°F229222217213209205201196189
24°F259249242237233227223216208
20°F285275269263258252247241232
16°F315304298290284278273266255

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
5,113
Cooling degree days, base 65°F
634
Growing degree days, base 40°F
5,482
Growing degree days, base 45°F
4,186
Growing degree days, base 50°F
3,054
Growing degree days, base 55°F
2,082
Growing degree days, base 60°F
1,274

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,00907
February83208
March704041
April3876150
May17534335
June31121540
July5212673
August10181635
September8772438
October3527173
November629043
December893012

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 0.6 km from Christiansburg. 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 USC00441692 (Christiansburg). Public domain.