Washington County climate

Washington County Frost Dates and Growing Season

NOAA 1991-2020 normals for Veyo Powerhouse, 16.4 km from Washington County, elevation 4600 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Veyo Powerhouse. 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 9 and the first fall freeze around November 5, a growing season of about 207 days.

Median at 36°F
last April 26, first October 25
Median at 32°F
last April 9, first November 5
Median at 28°F
last March 18, first November 16

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 17May 9May 4Apr 30Apr 26Apr 23Apr 19Apr 15Apr 9
32°FApr 28Apr 21Apr 16Apr 13Apr 9Apr 6Apr 2Mar 28Mar 18
28°FApr 11Apr 5Mar 31Mar 25Mar 18Mar 12Mar 8Mar 1Feb 24
24°FMar 22Mar 11Mar 5Feb 28Feb 25Feb 20Feb 16Feb 11Feb 3
20°FFeb 28Feb 20Feb 14Feb 8Feb 3Jan 29Jan 21Jan 11Dec 31
16°FFeb 6Jan 31Jan 25Jan 16Jan 9Jan 5Dec 31Dec 23Dec 13

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 9Oct 16Oct 19Oct 22Oct 25Oct 28Oct 31Nov 3Nov 7
32°FOct 21Oct 25Oct 29Nov 1Nov 5Nov 8Nov 11Nov 14Nov 18
28°FOct 31Nov 6Nov 10Nov 13Nov 16Nov 18Nov 21Nov 24Nov 29
24°FNov 11Nov 17Nov 21Nov 24Nov 27Dec 1Dec 5Dec 9Dec 14
20°FNov 24Nov 29Dec 3Dec 7Dec 11Dec 15Dec 20Dec 25Jan 1
16°FDec 1Dec 7Dec 12Dec 16Dec 23Dec 27Jan 1Jan 7Jan 20

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°F201194189184179174169162155
32°F232222217212207203198191185
28°F264257251244238232227220211
24°F305294287281275269263255243
20°F349336328320314306300294280
16°F365365361354348342336330318

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
98% of years
16°F or colder
74% 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
4,258
Cooling degree days, base 65°F
1,211
Growing degree days, base 40°F
6,417
Growing degree days, base 45°F
5,018
Growing degree days, base 50°F
3,821
Growing degree days, base 55°F
2,793
Growing degree days, base 60°F
1,927

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January83901
February66207
March541055
April3592143
May14655382
June22221650
July1402866
August1354818
September23161588
October23717266
November570044
December85901

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 16.4 km from Washington County. 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 USC00429136 (Veyo Powerhouse). Public domain.