Broussard climate

Broussard Frost Dates and Growing Season

NOAA 1991-2020 normals for Lafayette Rgnl AP, 6.9 km from Broussard, elevation 38 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lafayette Rgnl 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 February 13 and the first fall freeze around December 4, a growing season of about 299 days.

Median at 36°F
last March 3, first November 20
Median at 32°F
last February 13, first December 4
Median at 28°F
last January 27, first December 30

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°FMar 25Mar 17Mar 12Mar 7Mar 3Feb 28Feb 23Feb 16Feb 1
32°FMar 10Mar 3Feb 26Feb 19Feb 13Feb 5Jan 30Jan 24Jan 13
28°FFeb 28Feb 17Feb 5Jan 31Jan 27Jan 21Jan 14Jan 7Dec 29
24°FFeb 11Feb 1Jan 28Jan 22Jan 17Jan 12Jan 7Jan 1Dec 24
20°FFeb 4Jan 31Jan 25Jan 20Jan 15Jan 10Jan 7Jan 3Dec 30
16°F–––––––––

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

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°F297287278271265258252246236
32°F335322312306299292283274263
28°F365362352345337330320310297
24°F365365365365365365354344333
20°F365365365365365365365365360
16°F365365365365365365365365365

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
99% of years
28°F or colder
82% of years
24°F or colder
45% of years
20°F or colder
14% of years
16°F or colder
4% 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
1,377
Cooling degree days, base 65°F
3,007
Growing degree days, base 40°F
10,777
Growing degree days, base 45°F
9,004
Growing degree days, base 50°F
7,303
Growing degree days, base 55°F
5,722
Growing degree days, base 60°F
4,283

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January39215170
February25625222
March13773410
April38162575
May2360823
June0499949
July05671,032
August05731,038
September0441891
October34210642
November17954341
December34025208

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 6.9 km from Broussard. 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 USW00013976 (Lafayette Rgnl AP). Public domain.