Noatak climate

Noatak Frost Dates and Growing Season

NOAA 1991-2020 normals for Kivalina AP, 69.3 km from Noatak, elevation 10 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Kivalina AP. 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 June 10 and the first fall freeze around September 11, a growing season of about 92 days.

Median at 32°F
last June 10, first September 11
Median at 28°F
last June 1, first September 24

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°F–––––––––
32°FJun 23Jun 19Jun 16Jun 13Jun 10Jun 7Jun 3May 31May 24
28°FJun 12Jun 8Jun 5Jun 3Jun 1May 29May 23May 19May 14
24°FJun 3May 31May 28May 24May 20May 17May 14May 10May 6
20°FMay 26May 22May 18May 15May 12May 10May 7May 5May 2
16°FMay 21May 16May 13May 10May 8May 6May 4May 2Apr 28

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°F–––––––––
32°FAug 26Sep 1Sep 3Sep 7Sep 11Sep 15Sep 19Sep 23Sep 27
28°FSep 6Sep 13Sep 17Sep 21Sep 24Sep 27Sep 29Oct 3Oct 6
24°FSep 16Sep 22Sep 26Sep 29Oct 1Oct 4Oct 7Oct 10Oct 15
20°FSep 26Oct 1Oct 4Oct 7Oct 10Oct 12Oct 15Oct 18Oct 22
16°FOct 3Oct 8Oct 11Oct 14Oct 18Oct 20Oct 23Oct 26Oct 31

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°F877972666257514536
32°F114107101979288858072
28°F13412712111811411010610195
24°F151145140137133129124120112
20°F166160156153149145141136131
16°F178173168165161157153148143

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
15,402
Cooling degree days, base 65°F
4
Growing degree days, base 40°F
899
Growing degree days, base 45°F
460
Growing degree days, base 50°F
175
Growing degree days, base 55°F
50
Growing degree days, base 60°F
12

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January2,05200
February1,78400
March1,98700
April1,50600
May1,02201
June634133
July440385
August493051
September73105
October1,22300
November1,60800
December1,92400

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 69.3 km from Noatak. 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 USW00026642 (Kivalina AP). Public domain.