Summerdale climate

Summerdale Frost Dates and Growing Season

NOAA 1991-2020 normals for Robertsdale, 8.6 km from Summerdale, elevation 161 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Robertsdale. 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 March 5 and the first fall freeze around November 23, a growing season of about 264 days.

Median at 36°F
last March 21, first November 12
Median at 32°F
last March 5, first November 23
Median at 28°F
last February 21, first December 9

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°FApr 8Apr 2Mar 29Mar 25Mar 21Mar 17Mar 12Mar 7Feb 28
32°FMar 26Mar 19Mar 14Mar 10Mar 5Mar 1Feb 26Feb 20Feb 12
28°FMar 14Mar 6Feb 28Feb 25Feb 21Feb 16Feb 8Jan 31Jan 24
24°FMar 1Feb 23Feb 16Feb 9Feb 3Jan 31Jan 26Jan 17Jan 4
20°FFeb 20Feb 9Feb 2Jan 31Jan 23Jan 18Jan 10Jan 4Dec 27
16°FFeb 11Feb 6Feb 1Jan 28Jan 21Jan 15Jan 10Jan 5Jan 1

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°FOct 27Nov 1Nov 5Nov 8Nov 12Nov 16Nov 19Nov 23Nov 30
32°FNov 5Nov 11Nov 15Nov 19Nov 23Nov 28Dec 1Dec 6Dec 15
28°FNov 17Nov 24Dec 1Dec 4Dec 9Dec 18Dec 26Jan 2Jan 10
24°FDec 1Dec 10Dec 19Dec 28Jan 2Jan 6Jan 12Jan 19Feb 1
20°FDec 13Dec 26Jan 1Jan 5Jan 10Jan 16Jan 22Jan 31Feb 6
16°FDec 30Jan 3Jan 6Jan 10Jan 16Jan 22Jan 31Feb 3Feb 8

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°F265255247242236231226220210
32°F298284276269264258252245236
28°F330318310304295288281273261
24°F365352341334328321313305293
20°F365365365365363353343334321
16°F365365365365365365365365346

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
99% of years
24°F or colder
88% of years
20°F or colder
55% of years
16°F or colder
19% 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
1,804
Cooling degree days, base 65°F
2,359
Growing degree days, base 40°F
9,728
Growing degree days, base 45°F
7,995
Growing degree days, base 50°F
6,365
Growing degree days, base 55°F
4,868
Growing degree days, base 60°F
3,525

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January4748126
February33512160
March20538317
April7489466
May8261718
June0420870
July0496961
August0485950
September1358807
October58145553
November23633274
December41114164

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 8.6 km from Summerdale. 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 USC00016988 (Robertsdale). Public domain.