Cattaraugus County climate

Cattaraugus County Frost Dates and Growing Season

NOAA 1991-2020 normals for Little Valley, 11 km from Cattaraugus County, elevation 1625 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Little Valley. 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 May 17 and the first fall freeze around October 1, a growing season of about 136 days.

Median at 36°F
last May 31, first September 20
Median at 32°F
last May 17, first October 1
Median at 28°F
last May 3, first October 15

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°FJun 17Jun 10Jun 6Jun 3May 31May 28May 25May 21May 16
32°FMay 31May 27May 24May 21May 17May 14May 10May 6May 1
28°FMay 21May 16May 10May 7May 3Apr 30Apr 28Apr 25Apr 20
24°FMay 9May 2Apr 30Apr 26Apr 24Apr 21Apr 18Apr 14Apr 8
20°FApr 23Apr 19Apr 16Apr 13Apr 10Apr 7Apr 5Apr 3Mar 31
16°FApr 14Apr 10Apr 6Apr 4Apr 2Mar 31Mar 28Mar 24Mar 17

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 1Sep 9Sep 12Sep 16Sep 20Sep 23Sep 27Sep 30Oct 4
32°FSep 18Sep 23Sep 27Sep 29Oct 1Oct 4Oct 7Oct 11Oct 17
28°FOct 1Oct 4Oct 8Oct 12Oct 15Oct 19Oct 23Oct 29Nov 2
24°FOct 12Oct 19Oct 24Oct 28Nov 1Nov 2Nov 5Nov 9Nov 15
20°FOct 29Nov 2Nov 6Nov 9Nov 12Nov 15Nov 19Nov 22Nov 30
16°FNov 8Nov 12Nov 15Nov 19Nov 22Nov 26Nov 30Dec 4Dec 9

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°F1321251201151111061019486
32°F158152146141136132128122115
28°F186178172167163158153148139
24°F210204199194191186181175166
20°F235228223219214210206201193
16°F259251244239235231226221214

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
7,561
Cooling degree days, base 65°F
273
Growing degree days, base 40°F
3,899
Growing degree days, base 45°F
2,876
Growing degree days, base 50°F
1,999
Growing degree days, base 55°F
1,256
Growing degree days, base 60°F
668

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,33301
February1,18201
March1,07908
April670142
May35217191
June12353384
July47100518
August6274477
September20826282
October534281
November825013
December1,14702

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 11 km from Cattaraugus County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00304808 (Little Valley). Public domain.