Clarkson climate

Clarkson Frost Dates and Growing Season

NOAA 1991-2020 normals for Brockport, 2.8 km from Clarkson, elevation 498 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Brockport. 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 24 and the first fall freeze around October 30, a growing season of about 187 days.

Median at 36°F
last May 4, first October 14
Median at 32°F
last April 24, first October 30
Median at 28°F
last April 11, first November 10

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 18May 13May 10May 7May 4May 1Apr 30Apr 27Apr 23
32°FMay 7May 2Apr 29Apr 27Apr 24Apr 22Apr 19Apr 17Apr 12
28°FApr 22Apr 19Apr 17Apr 15Apr 11Apr 9Apr 6Apr 3Mar 31
24°FApr 14Apr 9Apr 6Apr 4Apr 2Mar 31Mar 28Mar 23Mar 18
20°FApr 6Apr 1Mar 30Mar 27Mar 24Mar 21Mar 17Mar 14Mar 9
16°FMar 29Mar 24Mar 20Mar 17Mar 15Mar 12Mar 9Mar 4Feb 27

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 5Oct 8Oct 11Oct 14Oct 18Oct 21Oct 25Nov 1
32°FOct 12Oct 19Oct 23Oct 27Oct 30Nov 1Nov 4Nov 7Nov 12
28°FOct 27Nov 1Nov 4Nov 7Nov 10Nov 12Nov 15Nov 18Nov 24
24°FNov 8Nov 12Nov 15Nov 18Nov 21Nov 24Nov 28Dec 1Dec 7
20°FNov 16Nov 20Nov 25Nov 29Dec 2Dec 5Dec 9Dec 13Dec 19
16°FNov 24Nov 30Dec 4Dec 7Dec 10Dec 14Dec 19Dec 23Dec 31

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°F183176171167163159155150144
32°F205200195191187183179173167
28°F230223218214211207203198192
24°F254247242238233229225220214
20°F276268263258254249244239232
16°F294286281277273268263258251

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
6,535
Cooling degree days, base 65°F
583
Growing degree days, base 40°F
4,683
Growing degree days, base 45°F
3,590
Growing degree days, base 50°F
2,648
Growing degree days, base 55°F
1,831
Growing degree days, base 60°F
1,138

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,22600
February1,09300
March96404
April583152
May25933265
June58104497
July9194651
August14178629
September12266398
October4286128
November736125
December1,04500

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 2.8 km from Clarkson. 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 USC00300937 (Brockport). Public domain.