Laporte climate

Laporte Frost Dates and Growing Season

NOAA 1991-2020 normals for Laporte, 0.1 km from Laporte, elevation 1966 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Laporte. 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 May 6 and the first fall freeze around October 7, a growing season of about 154 days.

Median at 36°F
last May 18, first September 29
Median at 32°F
last May 6, first October 7
Median at 28°F
last April 27, first October 20

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 30May 27May 24May 21May 18May 14May 11May 7May 1
32°FMay 22May 17May 13May 9May 6May 3Apr 30Apr 28Apr 22
28°FMay 12May 7May 2Apr 30Apr 27Apr 23Apr 20Apr 17Apr 12
24°FMay 2Apr 26Apr 21Apr 18Apr 15Apr 12Apr 8Apr 5Apr 1
20°FApr 19Apr 14Apr 10Apr 7Apr 5Apr 2Mar 31Mar 29Mar 22
16°FApr 8Apr 5Apr 2Mar 31Mar 30Mar 26Mar 22Mar 17Mar 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 17Sep 20Sep 23Sep 26Sep 29Oct 1Oct 3Oct 6Oct 10
32°FSep 24Sep 29Oct 2Oct 5Oct 7Oct 10Oct 14Oct 18Oct 24
28°FOct 5Oct 9Oct 13Oct 17Oct 20Oct 24Oct 28Nov 1Nov 4
24°FOct 16Oct 23Oct 27Oct 31Nov 1Nov 4Nov 8Nov 13Nov 18
20°FOct 31Nov 4Nov 8Nov 11Nov 14Nov 17Nov 21Nov 25Dec 1
16°FNov 9Nov 14Nov 18Nov 21Nov 25Nov 28Dec 1Dec 4Dec 11

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°F152145140137133130125121114
32°F174168162158154150145140133
28°F197191186181177172168163156
24°F221214209205200196191185178
20°F242235230226222218213208200
16°F265256251246242238233228221

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
7,537
Cooling degree days, base 65°F
282
Growing degree days, base 40°F
3,934
Growing degree days, base 45°F
2,915
Growing degree days, base 50°F
2,033
Growing degree days, base 55°F
1,290
Growing degree days, base 60°F
696

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,34701
February1,17000
March1,05207
April649245
May33214192
June10855400
July31112546
August5478490
September21321271
October551171
November85509
December1,17601

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 0.1 km from Laporte. 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 USC00364815 (Laporte). Public domain.