Lafayette climate

Lafayette Frost Dates and Growing Season

NOAA 1991-2020 normals for Lafayette 2W, 3.1 km from Lafayette, elevation 740 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lafayette 2W. 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 30, a growing season of about 204 days.

Median at 36°F
last April 21, first October 21
Median at 32°F
last April 9, first October 30
Median at 28°F
last March 26, first November 8

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

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 10Oct 14Oct 17Oct 19Oct 21Oct 24Oct 26Oct 29Nov 2
32°FOct 18Oct 22Oct 25Oct 27Oct 30Nov 1Nov 3Nov 7Nov 13
28°FOct 25Oct 31Nov 2Nov 5Nov 8Nov 12Nov 15Nov 19Nov 25
24°FNov 2Nov 8Nov 12Nov 16Nov 19Nov 23Nov 27Dec 2Dec 12
20°FNov 13Nov 21Nov 26Dec 1Dec 4Dec 11Dec 21Dec 30Jan 6
16°FNov 28Dec 5Dec 13Dec 22Dec 30Jan 2Jan 8Jan 15Jan 26

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°F205197191187183179175171165
32°F227219212207204200195190185
28°F257246239233227222216210203
24°F290278271265258251245238228
20°F330317307299290282275265255
16°F362348338334327321311302289

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
88% 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
2,958
Cooling degree days, base 65°F
1,602
Growing degree days, base 40°F
7,939
Growing degree days, base 45°F
6,341
Growing degree days, base 50°F
4,899
Growing degree days, base 55°F
3,616
Growing degree days, base 60°F
2,520

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January684044
February508163
March3636171
April17131320
May40148574
June1309757
July0425890
August0391856
September11231670
October15354375
November4115121
December616158

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 3.1 km from Lafayette. 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 USC00014502 (Lafayette 2W). Public domain.