Vienna climate

Vienna Frost Dates and Growing Season

NOAA 1991-2020 normals for Dixon Springs Agric Ctr, 20.5 km from Vienna, elevation 527 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Dixon Springs Agric Ctr. 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 14 and the first fall freeze around October 21, a growing season of about 189 days.

Median at 36°F
last April 24, first October 11
Median at 32°F
last April 14, first October 21
Median at 28°F
last April 2, 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 10May 5May 1Apr 28Apr 24Apr 21Apr 18Apr 15Apr 10
32°FApr 30Apr 24Apr 20Apr 17Apr 14Apr 11Apr 7Apr 3Mar 28
28°FApr 19Apr 13Apr 9Apr 5Apr 2Mar 31Mar 27Mar 22Mar 14
24°FApr 7Apr 2Mar 30Mar 25Mar 20Mar 16Mar 12Mar 7Feb 28
20°FMar 27Mar 20Mar 15Mar 11Mar 7Mar 3Feb 28Feb 24Feb 18
16°FMar 16Mar 10Mar 5Mar 1Feb 26Feb 22Feb 17Feb 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°FSep 29Oct 3Oct 6Oct 9Oct 11Oct 15Oct 18Oct 20Oct 24
32°FOct 6Oct 12Oct 16Oct 19Oct 21Oct 23Oct 26Oct 29Nov 2
28°FOct 16Oct 22Oct 25Oct 28Oct 31Nov 2Nov 5Nov 8Nov 15
24°FOct 27Nov 1Nov 4Nov 7Nov 11Nov 14Nov 18Nov 22Nov 28
20°FNov 7Nov 12Nov 16Nov 19Nov 23Nov 26Nov 30Dec 4Dec 10
16°FNov 14Nov 22Nov 26Nov 30Dec 3Dec 8Dec 12Dec 19Dec 27

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°F188182177173170165161155147
32°F208201197193189185180175169
28°F234226220215211206202197190
24°F260251245240235230224218211
20°F284277270265260254249243235
16°F311303294287282276270264254

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
4,206
Cooling degree days, base 65°F
1,389
Growing degree days, base 40°F
6,940
Growing degree days, base 45°F
5,542
Growing degree days, base 50°F
4,288
Growing degree days, base 55°F
3,175
Growing degree days, base 60°F
2,207

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January949012
February733025
March5405100
April24230271
May79122509
June7279721
July0385849
August2346809
September38180593
October23339297
November540385
December845018

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 20.5 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 USC00112353 (Dixon Springs Agric Ctr). Public domain.