Glasgow climate

Glasgow Frost Dates and Growing Season

NOAA 1991-2020 normals for Glasgow, 0.7 km from Glasgow, elevation 770 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Glasgow. 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 9 and the first fall freeze around October 27, a growing season of about 201 days.

Median at 36°F
last April 23, first October 19
Median at 32°F
last April 9, first October 27
Median at 28°F
last March 28, first November 5

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 3Apr 30Apr 26Apr 23Apr 20Apr 17Apr 13Apr 8
32°FApr 28Apr 21Apr 17Apr 13Apr 9Apr 6Apr 3Mar 30Mar 24
28°FApr 13Apr 6Apr 3Mar 31Mar 28Mar 24Mar 19Mar 14Mar 7
24°FApr 2Mar 28Mar 22Mar 17Mar 13Mar 8Mar 4Feb 28Feb 22
20°FMar 20Mar 14Mar 8Mar 4Mar 1Feb 26Feb 21Feb 13Feb 5
16°FMar 10Mar 2Feb 26Feb 21Feb 15Feb 10Feb 5Jan 31Jan 22

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°FOct 5Oct 10Oct 13Oct 16Oct 19Oct 22Oct 24Oct 27Oct 31
32°FOct 14Oct 19Oct 22Oct 24Oct 27Oct 31Nov 2Nov 5Nov 11
28°FOct 22Oct 27Nov 1Nov 3Nov 5Nov 9Nov 12Nov 17Nov 25
24°FNov 3Nov 7Nov 11Nov 15Nov 18Nov 24Nov 29Dec 4Dec 10
20°FNov 11Nov 18Nov 24Nov 30Dec 3Dec 7Dec 13Dec 19Dec 27
16°FNov 26Dec 3Dec 9Dec 15Dec 21Dec 25Dec 30Jan 5Jan 15

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°F199192187182179174171166158
32°F222214209205201197192187179
28°F252242235230225220215209202
24°F281272263258252246240233224
20°F311300292285278273267260250
16°F334325317310305299294286274

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
99% 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
3,616
Cooling degree days, base 65°F
1,637
Growing degree days, base 40°F
7,570
Growing degree days, base 45°F
6,091
Growing degree days, base 50°F
4,756
Growing degree days, base 55°F
3,566
Growing degree days, base 60°F
2,527

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January834025
February649136
March4638135
April20645314
May48155572
June2322769
July0437902
August0398863
September23211638
October18654351
November4726116
December732036

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 0.7 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 USC00153246 (Glasgow). Public domain.