North Pole climate

North Pole Frost Dates and Growing Season

NOAA 1991-2020 normals for N Pole 1N, 1.1 km from North Pole, elevation 496 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for N Pole 1N. 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 22 and the first fall freeze around September 2, a growing season of about 102 days.

Median at 36°F
last June 2, first August 22
Median at 32°F
last May 22, first September 2
Median at 28°F
last May 13, first September 14

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°FJun 21Jun 11Jun 6Jun 4Jun 2May 31May 29May 26May 22
32°FJun 4May 31May 28May 25May 22May 20May 18May 15May 12
28°FMay 26May 20May 17May 15May 13May 11May 8May 5May 2
24°FMay 14May 11May 8May 6May 3May 2Apr 30Apr 25Apr 21
20°FMay 7May 4May 2Apr 29Apr 26Apr 23Apr 20Apr 17Apr 13
16°FMay 3Apr 29Apr 24Apr 21Apr 18Apr 16Apr 13Apr 10Apr 7

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 7Aug 12Aug 16Aug 19Aug 22Aug 24Aug 27Aug 30Sep 2
32°FAug 20Aug 25Aug 28Aug 31Sep 2Sep 4Sep 7Sep 11Sep 17
28°FSep 1Sep 4Sep 7Sep 11Sep 14Sep 17Sep 20Sep 24Sep 29
24°FSep 10Sep 15Sep 19Sep 22Sep 25Sep 27Sep 30Oct 3Oct 7
20°FSep 18Sep 24Sep 28Sep 30Oct 3Oct 5Oct 8Oct 11Oct 15
16°FSep 26Sep 30Oct 3Oct 6Oct 9Oct 11Oct 14Oct 17Oct 21

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°F979187837976716658
32°F11911410910610298949083
28°F141136132128124120116111105
24°F161155150147143140137132124
20°F177172167163159155151147141
16°F188182179176173169165160154

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
14,025
Cooling degree days, base 65°F
24
Growing degree days, base 40°F
2,082
Growing degree days, base 45°F
1,387
Growing degree days, base 50°F
813
Growing degree days, base 55°F
387
Growing degree days, base 60°F
126

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January2,32000
February1,82000
March1,65200
April96202
May530058
June20910255
July14913329
August3282159
September662010
October1,26200
November1,91500
December2,21700

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 1.1 km from North Pole. 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 USC00509891 (N Pole 1N). Public domain.