Naknek climate

Naknek Frost Dates and Growing Season

NOAA 1991-2020 normals for King Salmon, 22.9 km from Naknek, elevation 63 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for King Salmon. 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 26 and the first fall freeze around September 15, a growing season of about 111 days.

Median at 36°F
last June 14, first September 1
Median at 32°F
last May 26, first September 15
Median at 28°F
last May 8, first September 27

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 4Jun 26Jun 21Jun 17Jun 14Jun 11Jun 7Jun 4May 31
32°FJun 11Jun 4May 31May 29May 26May 23May 19May 15May 9
28°FMay 25May 19May 14May 11May 8May 5May 2Apr 29Apr 23
24°FMay 9May 4May 1Apr 29Apr 26Apr 22Apr 19Apr 16Apr 11
20°FApr 30Apr 25Apr 22Apr 20Apr 16Apr 14Apr 11Apr 7Apr 4
16°FApr 22Apr 18Apr 14Apr 11Apr 9Apr 6Apr 4Apr 2Mar 30

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 16Aug 21Aug 25Aug 29Sep 1Sep 3Sep 6Sep 11Sep 16
32°FAug 31Sep 4Sep 7Sep 11Sep 15Sep 17Sep 20Sep 24Sep 29
28°FSep 11Sep 17Sep 20Sep 24Sep 27Sep 29Oct 1Oct 4Oct 10
24°FSep 23Sep 27Oct 1Oct 2Oct 5Oct 8Oct 11Oct 16Oct 21
20°FOct 1Oct 4Oct 8Oct 11Oct 14Oct 18Oct 21Oct 25Oct 31
16°FOct 6Oct 12Oct 16Oct 20Oct 23Oct 26Oct 29Nov 1Nov 7

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°F989186817773686153
32°F1331251201161111061029689
28°F162155150145142138133128121
24°F185178172167163159156152144
20°F202194189185181177173168161
16°F215208203199195191187182175

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
10,385
Cooling degree days, base 65°F
3
Growing degree days, base 40°F
1,977
Growing degree days, base 45°F
1,175
Growing degree days, base 50°F
566
Growing degree days, base 55°F
183
Growing degree days, base 60°F
32

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,49900
February1,20100
March1,28600
April86901
May600013
June3660109
July2582212
August2911179
September491048
October88703
November1,19900
December1,44000

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 22.9 km from Naknek. 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 USW00025503 (King Salmon). Public domain.