Ashland climate

Ashland Frost Dates and Growing Season

NOAA 1991-2020 normals for Petersburg 1E, 20.6 km from Ashland, elevation 600 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Petersburg 1E. 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 13 and the first fall freeze around October 21, a growing season of about 189 days.

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

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 12Oct 14Oct 17Oct 19Oct 23
32°FOct 7Oct 13Oct 16Oct 19Oct 21Oct 23Oct 25Oct 29Nov 3
28°FOct 19Oct 24Oct 26Oct 29Nov 1Nov 3Nov 6Nov 9Nov 14
24°FOct 28Nov 1Nov 4Nov 7Nov 11Nov 14Nov 18Nov 22Nov 28
20°FNov 7Nov 11Nov 14Nov 18Nov 21Nov 26Nov 29Dec 2Dec 9
16°FNov 13Nov 19Nov 24Nov 27Dec 1Dec 4Dec 8Dec 14Dec 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°F187181177173169166161157150
32°F209202197193189185181176170
28°F233224219214210207202198190
24°F255246241236231226222216210
20°F274266260255251247241236228
16°F294286280274268263258252244

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
5,644
Cooling degree days, base 65°F
1,056
Growing degree days, base 40°F
5,852
Growing degree days, base 45°F
4,640
Growing degree days, base 50°F
3,563
Growing degree days, base 55°F
2,607
Growing degree days, base 60°F
1,773

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,21300
February98204
March758028
April38510167
May12679424
June8225667
July1325788
August3269731
September70125505
October34221207
November698239
December1,05802

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 20.6 km from Ashland. 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 USC00116765 (Petersburg 1E). Public domain.