Lacombe climate

Lacombe Frost Dates and Growing Season

NOAA 1991-2020 normals for Slidell AP, 12 km from Lacombe, elevation 27 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Slidell AP. 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 March 3 and the first fall freeze around November 21, a growing season of about 263 days.

Median at 36°F
last March 20, first November 8
Median at 32°F
last March 3, first November 21
Median at 28°F
last February 14, first December 6

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°FApr 10Apr 3Mar 30Mar 25Mar 20Mar 16Mar 11Mar 4Feb 25
32°FMar 26Mar 18Mar 13Mar 9Mar 3Feb 27Feb 22Feb 16Feb 4
28°FMar 13Mar 5Feb 28Feb 20Feb 14Feb 6Jan 31Jan 25Jan 14
24°FMar 1Feb 16Feb 5Feb 1Jan 27Jan 20Jan 13Jan 3Dec 25
20°FFeb 12Jan 31Jan 27Jan 22Jan 17Jan 11Jan 5Dec 30Dec 23
16°FJan 31Jan 27Jan 22Jan 17Jan 11Jan 8Jan 2Dec 30Dec 15

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 26Nov 1Nov 3Nov 5Nov 8Nov 12Nov 16Nov 21Nov 28
32°FNov 4Nov 8Nov 13Nov 17Nov 21Nov 25Dec 1Dec 5Dec 13
28°FNov 14Nov 22Nov 28Dec 2Dec 6Dec 12Dec 25Jan 2Jan 12
24°FNov 30Dec 7Dec 14Dec 23Dec 30Jan 4Jan 10Jan 18Feb 1
20°FDec 11Dec 23Dec 29Jan 2Jan 7Jan 12Jan 17Jan 24Feb 1
16°FDec 15Dec 30Jan 2Jan 5Jan 9Jan 12Jan 19Jan 24Jan 29

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°F264253246240234229223217207
32°F296284276269263258252245236
28°F336325315307300293286275263
24°F365360349341335328320310298
20°F365365365365365363354343333
16°F365365365365365365365365360

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
99% of years
24°F or colder
81% of years
20°F or colder
38% of years
16°F or colder
11% 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
1,612
Cooling degree days, base 65°F
2,634
Growing degree days, base 40°F
10,175
Growing degree days, base 45°F
8,416
Growing degree days, base 50°F
6,753
Growing degree days, base 55°F
5,223
Growing degree days, base 60°F
3,845

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January43411145
February29621191
March17750351
April57117511
May4294755
June0459909
July0530995
August0529993
September1398847
October49171588
November21934284
December37419183

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 12 km from Lacombe. 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 USW00053865 (Slidell AP). Public domain.