Biddeford climate

Biddeford Frost Dates and Growing Season

NOAA 1991-2020 normals for Kennebunkport, 14.8 km from Biddeford, elevation 20 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Kennebunkport. 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 9 and the first fall freeze around October 3, a growing season of about 146 days.

Median at 36°F
last May 20, first September 24
Median at 32°F
last May 9, first October 3
Median at 28°F
last April 29, first October 15

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 2May 29May 25May 22May 20May 18May 15May 12May 7
32°FMay 22May 18May 14May 11May 9May 6May 4May 1Apr 28
28°FMay 12May 8May 4May 1Apr 29Apr 26Apr 23Apr 20Apr 16
24°FMay 1Apr 24Apr 20Apr 17Apr 13Apr 10Apr 7Apr 5Apr 1
20°FApr 20Apr 12Apr 7Apr 5Apr 2Mar 31Mar 29Mar 25Mar 18
16°FApr 5Mar 31Mar 29Mar 25Mar 22Mar 18Mar 16Mar 12Mar 8

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 9Sep 16Sep 19Sep 22Sep 24Sep 27Sep 29Oct 2Oct 6
32°FSep 20Sep 26Sep 29Oct 1Oct 3Oct 6Oct 9Oct 13Oct 19
28°FSep 30Oct 5Oct 8Oct 12Oct 15Oct 19Oct 22Oct 26Nov 1
24°FOct 9Oct 16Oct 21Oct 24Oct 29Nov 1Nov 4Nov 7Nov 12
20°FOct 26Oct 31Nov 4Nov 8Nov 11Nov 15Nov 18Nov 22Nov 28
16°FNov 8Nov 14Nov 19Nov 22Nov 27Nov 30Dec 2Dec 5Dec 11

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°F144138134130126123119113106
32°F165158154150146143139135128
28°F190184178173169165161155149
24°F216210205200196191187181173
20°F246236231226222217213207198
16°F272264258254249244239233225

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
7,380
Cooling degree days, base 65°F
251
Growing degree days, base 40°F
3,748
Growing degree days, base 45°F
2,731
Growing degree days, base 50°F
1,878
Growing degree days, base 55°F
1,178
Growing degree days, base 60°F
627

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,30500
February1,13000
March1,02501
April686016
May4034117
June13935348
July33105538
August4584504
September19821283
October526163
November78807
December1,10401

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 14.8 km from Biddeford. 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 USC00174193 (Kennebunkport). Public domain.