Olean climate

Olean Frost Dates and Growing Season

NOAA 1991-2020 normals for Olean, 1.9 km from Olean, elevation 1420 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Olean. 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 7 and the first fall freeze around October 11, a growing season of about 156 days.

Median at 36°F
last May 20, first October 1
Median at 32°F
last May 7, first October 11
Median at 28°F
last April 26, first October 24

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 1May 28May 26May 23May 20May 17May 14May 9May 5
32°FMay 22May 18May 13May 10May 7May 4May 1Apr 28Apr 23
28°FMay 9May 5May 2Apr 30Apr 26Apr 23Apr 21Apr 18Apr 14
24°FApr 29Apr 23Apr 20Apr 17Apr 15Apr 12Apr 9Apr 5Apr 2
20°FApr 17Apr 12Apr 8Apr 5Apr 3Apr 2Mar 31Mar 26Mar 21
16°FApr 5Apr 2Mar 31Mar 29Mar 25Mar 22Mar 19Mar 16Mar 11

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 18Sep 22Sep 25Sep 28Oct 1Oct 3Oct 5Oct 8Oct 12
32°FSep 29Oct 3Oct 6Oct 9Oct 11Oct 14Oct 17Oct 21Oct 25
28°FOct 10Oct 15Oct 19Oct 22Oct 24Oct 27Oct 30Nov 2Nov 6
24°FOct 23Oct 28Oct 31Nov 2Nov 5Nov 7Nov 10Nov 13Nov 17
20°FNov 2Nov 6Nov 10Nov 12Nov 15Nov 18Nov 21Nov 25Dec 1
16°FNov 10Nov 15Nov 18Nov 21Nov 25Nov 29Dec 1Dec 6Dec 12

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°F152145140135131128124119112
32°F175167163159156152147142136
28°F199192188183180175171165158
24°F222216211207204200195190183
20°F246238234229226221217212205
16°F268259254249245240236231224

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
7,122
Cooling degree days, base 65°F
356
Growing degree days, base 40°F
4,238
Growing degree days, base 45°F
3,184
Growing degree days, base 50°F
2,261
Growing degree days, base 55°F
1,469
Growing degree days, base 60°F
822

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,32001
February1,13101
March1,020010
April617149
May29617227
June8360429
July22135578
August3799527
September16842330
October496396
November813013
December1,11901

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 1.9 km from Olean. 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 USC00306196 (Olean). Public domain.