Homer climate

Homer Frost Dates and Growing Season

NOAA 1991-2020 normals for Homer AP, 3.3 km from Homer, elevation 64 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Homer 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 10 and the first fall freeze around September 29, a growing season of about 141 days.

Median at 36°F
last May 28, first September 16
Median at 32°F
last May 10, first September 29
Median at 28°F
last April 23, first October 11

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 8Jun 4Jun 1May 30May 28May 26May 23May 19May 14
32°FMay 23May 19May 16May 13May 10May 7May 4Apr 30Apr 27
28°FMay 7May 2Apr 30Apr 26Apr 23Apr 20Apr 16Apr 12Apr 9
24°FApr 22Apr 16Apr 12Apr 9Apr 7Apr 5Apr 3Apr 1Mar 27
20°FApr 12Apr 7Apr 4Apr 2Mar 31Mar 29Mar 26Mar 22Mar 15
16°FApr 6Apr 2Mar 31Mar 28Mar 24Mar 20Mar 16Mar 10Mar 3

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°FSep 1Sep 5Sep 9Sep 12Sep 16Sep 19Sep 21Sep 24Sep 28
32°FSep 14Sep 19Sep 23Sep 26Sep 29Oct 1Oct 4Oct 7Oct 13
28°FSep 28Oct 1Oct 4Oct 7Oct 11Oct 14Oct 18Oct 22Oct 28
24°FOct 7Oct 13Oct 17Oct 21Oct 24Oct 28Nov 1Nov 4Nov 9
20°FOct 19Oct 25Oct 28Nov 1Nov 4Nov 7Nov 10Nov 14Nov 20
16°FOct 28Nov 2Nov 6Nov 9Nov 13Nov 17Nov 21Nov 25Dec 2

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°F1281221161131081051019690
32°F160154149145141137132128121
28°F190184178174170167162157149
24°F217211206202198194190184177
20°F238231226221217213209205197
16°F261251245240236231226221213

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
9,084
Cooling degree days, base 65°F
0
Growing degree days, base 40°F
1,977
Growing degree days, base 45°F
1,130
Growing degree days, base 50°F
501
Growing degree days, base 55°F
130
Growing degree days, base 60°F
11

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,22800
February1,02800
March1,08200
April78900
May589011
June390081
July2740192
August3010167
September465045
October76905
November1,01400
December1,15600

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 3.3 km from Homer. 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 USW00025507 (Homer AP). Public domain.