Ridge Farm climate

Ridge Farm Frost Dates and Growing Season

NOAA 1991-2020 normals for Sidell 4N, 16.6 km from Ridge Farm, elevation 672 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sidell 4N. 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 19, a growing season of about 181 days.

Median at 36°F
last April 29, first October 9
Median at 32°F
last April 19, first October 19
Median at 28°F
last April 6, first October 30

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 13May 7May 4May 1Apr 29Apr 26Apr 23Apr 20Apr 17
32°FMay 3Apr 28Apr 24Apr 21Apr 19Apr 16Apr 13Apr 9Apr 4
28°FApr 21Apr 16Apr 12Apr 8Apr 6Apr 3Apr 1Mar 29Mar 24
24°FApr 11Apr 6Apr 2Mar 31Mar 28Mar 25Mar 21Mar 17Mar 11
20°FApr 2Mar 29Mar 24Mar 20Mar 17Mar 14Mar 10Mar 6Mar 1
16°FMar 25Mar 18Mar 15Mar 11Mar 8Mar 4Mar 1Feb 26Feb 18

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 25Sep 30Oct 3Oct 6Oct 9Oct 11Oct 14Oct 18Oct 21
32°FOct 5Oct 10Oct 13Oct 16Oct 19Oct 21Oct 24Oct 27Nov 1
28°FOct 15Oct 20Oct 24Oct 27Oct 30Nov 1Nov 3Nov 7Nov 14
24°FOct 28Nov 1Nov 3Nov 6Nov 9Nov 13Nov 17Nov 21Nov 27
20°FNov 4Nov 9Nov 13Nov 17Nov 20Nov 24Nov 27Dec 1Dec 8
16°FNov 12Nov 18Nov 23Nov 27Nov 30Dec 3Dec 8Dec 13Dec 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°F178173168165162158155150143
32°F200193189185181177174169162
28°F222215211207203199195191183
24°F249240235230226221217212205
20°F270262256251247242238232225
16°F290282276271265261255251243

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
5,854
Cooling degree days, base 65°F
975
Growing degree days, base 40°F
5,658
Growing degree days, base 45°F
4,470
Growing degree days, base 50°F
3,411
Growing degree days, base 55°F
2,471
Growing degree days, base 60°F
1,656

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,24301
February1,01503
March788238
April4159145
May14786412
June14227663
July3286749
August8236693
September77109484
October35820190
November718131
December1,06903

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 16.6 km from Ridge Farm. 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 USC00117952 (Sidell 4N). Public domain.