Trout Lake climate

Trout Lake Frost Dates and Growing Season

NOAA 1991-2020 normals for Mt Adams RS, 1 km from Trout Lake, elevation 1950 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mt Adams RS. 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 18 and the first fall freeze around September 25, a growing season of about 125 days.

Median at 36°F
last June 13, first September 7
Median at 32°F
last May 18, first September 25
Median at 28°F
last April 29, first October 9

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°FJul 2Jun 26Jun 21Jun 17Jun 13Jun 9Jun 4May 31May 23
32°FJun 12Jun 3May 29May 22May 18May 14May 10May 7May 1
28°FMay 16May 9May 5May 2Apr 29Apr 27Apr 23Apr 18Apr 11
24°FApr 28Apr 19Apr 12Apr 6Apr 1Mar 27Mar 22Mar 15Mar 8
20°FMar 31Mar 18Mar 12Mar 6Mar 2Feb 27Feb 23Feb 17Feb 6
16°FMar 9Mar 2Feb 25Feb 19Feb 15Feb 8Feb 1Jan 18Jan 5

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°FAug 20Aug 29Sep 1Sep 4Sep 7Sep 10Sep 14Sep 19Sep 25
32°FSep 4Sep 11Sep 16Sep 21Sep 25Sep 28Oct 1Oct 4Oct 10
28°FSep 21Sep 29Oct 2Oct 5Oct 9Oct 13Oct 17Oct 23Nov 1
24°FOct 5Oct 13Oct 18Oct 23Oct 27Nov 1Nov 5Nov 11Nov 18
20°FOct 19Oct 29Nov 3Nov 11Nov 16Nov 20Nov 25Dec 1Dec 10
16°FNov 3Nov 14Nov 22Nov 27Dec 1Dec 5Dec 11Dec 21Jan 3

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°F11110195898479726655
32°F15114113613012511911410593
28°F191181172167161156151144131
24°F241228220213207200192184173
20°F290276267260254247240229214
16°F331320309302293285276267253

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
99% 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
6,517
Cooling degree days, base 65°F
254
Growing degree days, base 40°F
3,775
Growing degree days, base 45°F
2,704
Growing degree days, base 50°F
1,829
Growing degree days, base 55°F
1,127
Growing degree days, base 60°F
600

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,01700
February84400
March79702
April583129
May3545154
June19022286
July51108522
August5599509
September20620274
October544052
November82502
December1,05200

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 1 km from Trout Lake. 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 USC00455659 (Mt Adams RS). Public domain.