Big Run climate

Big Run Frost Dates and Growing Season

NOAA 1991-2020 normals for Grampian 1E, 24.4 km from Big Run, elevation 1510 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Grampian 1E. 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 4 and the first fall freeze around October 13, a growing season of about 160 days.

Median at 36°F
last May 16, first October 1
Median at 32°F
last May 4, first October 13
Median at 28°F
last April 23, first October 27

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 30May 26May 23May 20May 16May 13May 9May 4Apr 30
32°FMay 21May 15May 11May 7May 4Apr 30Apr 28Apr 25Apr 20
28°FMay 10May 4Apr 30Apr 26Apr 23Apr 19Apr 16Apr 12Apr 6
24°FApr 24Apr 19Apr 15Apr 11Apr 8Apr 6Apr 3Mar 31Mar 26
20°FApr 12Apr 7Apr 4Apr 1Mar 30Mar 27Mar 24Mar 20Mar 15
16°FApr 3Mar 30Mar 27Mar 24Mar 21Mar 18Mar 15Mar 10Mar 5

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 19Sep 23Sep 25Sep 28Oct 1Oct 2Oct 5Oct 8Oct 12
32°FSep 30Oct 3Oct 6Oct 10Oct 13Oct 16Oct 19Oct 23Oct 28
28°FOct 11Oct 15Oct 20Oct 23Oct 27Oct 30Nov 2Nov 5Nov 10
24°FOct 25Nov 1Nov 3Nov 6Nov 9Nov 12Nov 15Nov 18Nov 23
20°FNov 6Nov 11Nov 14Nov 17Nov 20Nov 23Nov 27Dec 1Dec 6
16°FNov 14Nov 19Nov 24Nov 27Dec 1Dec 4Dec 7Dec 12Dec 18

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°F159151146141137133129124117
32°F182175169164160155150145138
28°F205198193189184181177172164
24°F233226221216212208203197190
20°F257249244239235231226222215
16°F279271265260255250245239232

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
6,899
Cooling degree days, base 65°F
390
Growing degree days, base 40°F
4,344
Growing degree days, base 45°F
3,274
Growing degree days, base 50°F
2,345
Growing degree days, base 55°F
1,543
Growing degree days, base 60°F
883

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,29700
February1,10201
March958013
April568162
May26817247
June6467454
July19152598
August35111541
September17039326
October497392
November803011
December1,11900

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 24.4 km from Big Run. 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 USC00363417 (Grampian 1E). Public domain.