Orleans climate

Orleans Frost Dates and Growing Season

NOAA 1991-2020 normals for Spirit Lake, 4.7 km from Orleans, elevation 1420 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Spirit Lake. 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 28 and the first fall freeze around October 11, a growing season of about 164 days.

Median at 36°F
last May 6, first October 1
Median at 32°F
last April 28, first October 11
Median at 28°F
last April 19, first October 21

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

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

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°F163156152149145142139134127
32°F183176172168164159155150145
28°F205198193187183180176170163
24°F221215211207203198194188182
20°F240232227223219215211206198
16°F257248243238234231226221214

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
7,678
Cooling degree days, base 65°F
682
Growing degree days, base 40°F
4,709
Growing degree days, base 45°F
3,678
Growing degree days, base 50°F
2,751
Growing degree days, base 55°F
1,935
Growing degree days, base 60°F
1,244

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,53300
February1,27000
March1,011011
April587270
May25333274
June39152563
July7246704
August16176625
September14067387
October5096110
November94208
December1,37200

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 4.7 km from Orleans. 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 USC00137859 (Spirit Lake). Public domain.