Wellsville climate

Wellsville Frost Dates and Growing Season

NOAA 1991-2020 normals for Logan 5 Sw Exp Farm, 4.6 km from Wellsville, elevation 4488 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Logan 5 Sw Exp Farm. 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 12 and the first fall freeze around September 28, a growing season of about 138 days.

Median at 36°F
last May 31, first September 18
Median at 32°F
last May 12, first September 28
Median at 28°F
last April 28, first October 9

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 16Jun 11Jun 7Jun 3May 31May 28May 24May 20May 14
32°FMay 29May 22May 18May 15May 12May 9May 7May 3Apr 30
28°FMay 12May 8May 4May 1Apr 28Apr 25Apr 21Apr 16Apr 9
24°FMay 1Apr 24Apr 18Apr 12Apr 8Apr 3Mar 31Mar 25Mar 16
20°FApr 11Apr 3Mar 31Mar 25Mar 20Mar 16Mar 13Mar 9Mar 5
16°FMar 28Mar 20Mar 15Mar 12Mar 9Mar 6Mar 4Mar 2Feb 25

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 4Sep 9Sep 12Sep 15Sep 18Sep 21Sep 24Sep 28Oct 2
32°FSep 14Sep 18Sep 22Sep 25Sep 28Oct 1Oct 4Oct 8Oct 12
28°FSep 26Sep 30Oct 4Oct 6Oct 9Oct 12Oct 15Oct 19Oct 24
24°FOct 6Oct 12Oct 16Oct 19Oct 23Oct 25Oct 29Nov 2Nov 7
20°FOct 17Oct 23Oct 27Oct 31Nov 3Nov 6Nov 10Nov 16Nov 21
16°FOct 27Nov 1Nov 8Nov 12Nov 16Nov 20Nov 23Nov 26Dec 1

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°F1301231181141091051019486
32°F157151146142138134129124117
28°F187180174169164161156151143
24°F223213206200195190185180170
20°F248241236230227221216208199
16°F272264258253248242237232223

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
7,314
Cooling degree days, base 65°F
447
Growing degree days, base 40°F
4,129
Growing degree days, base 45°F
3,087
Growing degree days, base 50°F
2,208
Growing degree days, base 55°F
1,483
Growing degree days, base 60°F
895

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,33100
February1,08800
March85405
April591034
May3534166
June12353384
July15203652
August22161604
September18826304
October561055
November90203
December1,28500

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 4.6 km from Wellsville. 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 USC00425194 (Logan 5 Sw Exp Farm). Public domain.