Glasgow climate

Glasgow Frost Dates and Growing Season

NOAA 1991-2020 normals for New Franklin 1W, 24.6 km from Glasgow, elevation 641 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for New Franklin 1W. 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 13 and the first fall freeze around October 22, a growing season of about 191 days.

Median at 36°F
last April 25, first October 12
Median at 32°F
last April 13, first October 22
Median at 28°F
last April 2, first November 1

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 9May 4May 1Apr 28Apr 25Apr 21Apr 18Apr 14Apr 9
32°FApr 29Apr 23Apr 19Apr 16Apr 13Apr 9Apr 6Apr 3Mar 29
28°FApr 18Apr 12Apr 7Apr 5Apr 2Mar 31Mar 27Mar 22Mar 17
24°FApr 7Apr 2Mar 30Mar 26Mar 22Mar 19Mar 15Mar 11Mar 5
20°FMar 30Mar 23Mar 19Mar 15Mar 11Mar 8Mar 5Mar 1Feb 23
16°FMar 20Mar 13Mar 9Mar 6Mar 3Feb 28Feb 25Feb 20Feb 13

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 27Oct 2Oct 6Oct 9Oct 12Oct 15Oct 17Oct 20Oct 24
32°FOct 7Oct 14Oct 17Oct 20Oct 22Oct 25Oct 28Oct 31Nov 3
28°FOct 20Oct 25Oct 29Oct 31Nov 1Nov 4Nov 7Nov 10Nov 16
24°FOct 31Nov 2Nov 5Nov 8Nov 11Nov 14Nov 17Nov 22Nov 29
20°FNov 6Nov 11Nov 15Nov 18Nov 21Nov 24Nov 28Dec 3Dec 8
16°FNov 13Nov 18Nov 23Nov 27Nov 30Dec 4Dec 8Dec 14Dec 21

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°F189182177173169165161154149
32°F213206200196191187184179173
28°F234227222217212209205200193
24°F257249242238234229225219212
20°F279270264259255250245240232
16°F298290283277273268262256248

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
5,215
Cooling degree days, base 65°F
1,244
Growing degree days, base 40°F
6,253
Growing degree days, base 45°F
4,985
Growing degree days, base 50°F
3,851
Growing degree days, base 55°F
2,851
Growing degree days, base 60°F
1,980

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,14502
February90209
March672361
April34617191
May11694448
June10259699
July1377842
August3330792
September67140525
October31423225
November645153
December99507

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 24.6 km from Glasgow. 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 USC00236012 (New Franklin 1W). Public domain.