Yakutat climate

Yakutat Frost Dates and Growing Season

NOAA 1991-2020 normals for Yakutat State AP, 5 km from Yakutat, elevation 33 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Yakutat State 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 May 20 and the first fall freeze around September 23, a growing season of about 124 days.

Median at 36°F
last June 5, first September 3
Median at 32°F
last May 20, first September 23
Median at 28°F
last May 1, first October 7

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 17Jun 13Jun 10Jun 7Jun 5Jun 2Jun 1May 29May 25
32°FMay 31May 28May 25May 22May 20May 17May 13May 9May 3
28°FMay 18May 13May 8May 4May 1Apr 29Apr 26Apr 22Apr 17
24°FApr 30Apr 24Apr 20Apr 16Apr 13Apr 10Apr 7Apr 4Mar 31
20°FApr 16Apr 10Apr 6Apr 4Apr 1Mar 31Mar 27Mar 22Mar 14
16°FApr 5Apr 1Mar 29Mar 26Mar 23Mar 19Mar 15Mar 11Mar 4

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 17Aug 24Aug 29Sep 1Sep 3Sep 7Sep 11Sep 16Sep 23
32°FSep 5Sep 11Sep 16Sep 20Sep 23Sep 27Oct 1Oct 3Oct 8
28°FSep 20Sep 27Oct 1Oct 4Oct 7Oct 11Oct 16Oct 21Oct 28
24°FOct 5Oct 11Oct 18Oct 22Oct 26Oct 30Nov 2Nov 6Nov 13
20°FOct 20Oct 28Nov 1Nov 4Nov 7Nov 11Nov 15Nov 19Nov 25
16°FOct 31Nov 6Nov 11Nov 15Nov 18Nov 22Nov 26Dec 1Dec 9

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°F11110498939085817670
32°F147139133128124119115109102
28°F184175170165161156150144135
24°F217209204198195190184178169
20°F243233227222218213208202194
16°F271259251244240234228222214

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
8,706
Cooling degree days, base 65°F
0
Growing degree days, base 40°F
1,923
Growing degree days, base 45°F
1,071
Growing degree days, base 50°F
448
Growing degree days, base 55°F
91
Growing degree days, base 60°F
7

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,12800
February96200
March1,02600
April79200
May600013
June393077
July2980168
August3210147
September468040
October71803
November93900
December1,06200

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 5 km from Yakutat. 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 USW00025339 (Yakutat State AP). Public domain.