Healy climate

Healy Frost Dates and Growing Season

NOAA 1991-2020 normals for Healy, 1.8 km from Healy, elevation 1417 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Healy. 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 27 and the first fall freeze around September 1, a growing season of about 97 days.

Median at 36°F
last June 8, first August 22
Median at 32°F
last May 27, first September 1
Median at 28°F
last May 12, first September 13

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 27Jun 18Jun 14Jun 10Jun 8Jun 5Jun 3May 31May 27
32°FJun 10Jun 5Jun 1May 30May 27May 23May 18May 15May 11
28°FMay 30May 25May 19May 16May 12May 10May 7May 3Apr 30
24°FMay 19May 13May 9May 5May 3May 1Apr 28Apr 24Apr 19
20°FMay 11May 5May 2Apr 29Apr 26Apr 23Apr 19Apr 15Apr 11
16°FMay 3Apr 29Apr 25Apr 22Apr 18Apr 15Apr 12Apr 9Apr 6

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 8Aug 13Aug 16Aug 19Aug 22Aug 25Aug 28Sep 1Sep 6
32°FAug 18Aug 22Aug 26Aug 29Sep 1Sep 4Sep 8Sep 14Sep 19
28°FAug 27Sep 1Sep 5Sep 9Sep 13Sep 17Sep 20Sep 24Sep 29
24°FSep 9Sep 13Sep 17Sep 20Sep 23Sep 26Sep 29Oct 2Oct 7
20°FSep 16Sep 21Sep 25Sep 28Oct 1Oct 4Oct 7Oct 10Oct 14
16°FSep 23Sep 28Oct 1Oct 4Oct 7Oct 10Oct 13Oct 16Oct 20

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°F938680767368635747
32°F1201121061019791888276
28°F14413713212712111711110597
24°F162156151146142137133126119
20°F177170165161157152149143136
16°F189183178175171166161155148

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
13,273
Cooling degree days, base 65°F
15
Growing degree days, base 40°F
1,837
Growing degree days, base 45°F
1,152
Growing degree days, base 50°F
620
Growing degree days, base 55°F
270
Growing degree days, base 60°F
83

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January2,02700
February1,58600
March1,62300
April1,01102
May608031
June2916182
July2256254
August3783127
September669022
October1,22503
November1,70100
December1,93000

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 1.8 km from Healy. 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 USC00503585 (Healy). Public domain.