Vienna climate

Vienna Frost Dates and Growing Season

NOAA 1991-2020 normals for Vienna 2 Wnw, 3.4 km from Vienna, elevation 770 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Vienna 2 Wnw. 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 8 and the first fall freeze around October 26, a growing season of about 200 days.

Median at 36°F
last April 21, first October 16
Median at 32°F
last April 8, first October 26
Median at 28°F
last March 28, first November 5

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 7May 2Apr 28Apr 24Apr 21Apr 17Apr 13Apr 9Apr 2
32°FApr 27Apr 21Apr 15Apr 11Apr 8Apr 5Mar 31Mar 27Mar 21
28°FApr 13Apr 7Apr 3Mar 31Mar 28Mar 24Mar 20Mar 16Mar 10
24°FApr 3Mar 29Mar 25Mar 21Mar 16Mar 13Mar 8Mar 4Feb 27
20°FMar 25Mar 18Mar 13Mar 9Mar 5Mar 2Feb 27Feb 21Feb 13
16°FMar 15Mar 10Mar 5Mar 1Feb 26Feb 22Feb 16Feb 10Feb 2

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 6Oct 10Oct 12Oct 16Oct 19Oct 22Oct 24Oct 28
32°FOct 12Oct 17Oct 21Oct 24Oct 26Oct 29Nov 1Nov 3Nov 8
28°FOct 23Oct 28Nov 1Nov 3Nov 5Nov 8Nov 13Nov 16Nov 24
24°FNov 1Nov 5Nov 10Nov 13Nov 17Nov 21Nov 25Nov 29Dec 5
20°FNov 10Nov 16Nov 21Nov 25Nov 28Dec 1Dec 6Dec 10Dec 18
16°FNov 19Nov 27Dec 1Dec 5Dec 10Dec 14Dec 19Dec 23Dec 29

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°F198190185180176172167160153
32°F220214208204200196191184176
28°F247238232228223219214208201
24°F270261255250245240235229221
20°F293284277271267262257250241
16°F317307299293286280274268260

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
4,272
Cooling degree days, base 65°F
1,607
Growing degree days, base 40°F
7,127
Growing degree days, base 45°F
5,746
Growing degree days, base 50°F
4,507
Growing degree days, base 55°F
3,401
Growing degree days, base 60°F
2,433

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January964112
February743125
March55814113
April25843275
May78134522
June9317759
July0454919
August1409872
September43189596
October23839298
November535596
December845020

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 3.4 km from Vienna. 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 USC00238620 (Vienna 2 Wnw). Public domain.