Phippsburg climate

Phippsburg Frost Dates and Growing Season

NOAA 1991-2020 normals for Bath, 12.7 km from Phippsburg, elevation 25 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bath. 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 October 6, a growing season of about 149 days.

Median at 36°F
last May 22, first September 26
Median at 32°F
last May 10, first October 6
Median at 28°F
last April 29, first October 19

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 30May 27May 24May 22May 20May 17May 15May 10
32°FMay 23May 19May 16May 13May 10May 8May 5May 2Apr 28
28°FMay 10May 5May 3May 1Apr 29Apr 26Apr 23Apr 21Apr 17
24°FApr 24Apr 20Apr 17Apr 15Apr 12Apr 9Apr 7Apr 5Apr 3
20°FApr 12Apr 8Apr 6Apr 4Apr 2Mar 31Mar 29Mar 24Mar 19
16°FApr 4Apr 1Mar 30Mar 27Mar 24Mar 21Mar 18Mar 15Mar 12

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 15Sep 19Sep 22Sep 24Sep 26Sep 29Oct 1Oct 3Oct 7
32°FSep 25Sep 30Oct 1Oct 4Oct 6Oct 8Oct 11Oct 15Oct 21
28°FOct 4Oct 8Oct 12Oct 16Oct 19Oct 22Oct 25Oct 29Nov 3
24°FOct 19Oct 23Oct 27Oct 30Nov 1Nov 4Nov 7Nov 10Nov 14
20°FNov 1Nov 5Nov 9Nov 12Nov 14Nov 17Nov 20Nov 23Nov 27
16°FNov 11Nov 15Nov 19Nov 22Nov 25Nov 28Dec 1Dec 3Dec 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°F142137133130127123119115110
32°F167161156152149145142137131
28°F192185181176172169165160154
24°F217212208204201197194190183
20°F243237232229225222218214208
16°F263257253248244241236232227

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
7,668
Cooling degree days, base 65°F
259
Growing degree days, base 40°F
3,770
Growing degree days, base 45°F
2,768
Growing degree days, base 50°F
1,918
Growing degree days, base 55°F
1,216
Growing degree days, base 60°F
658

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,37300
February1,21600
March1,06603
April698011
May4052111
June12929352
July20113558
August2988524
September19727288
October526064
November83407
December1,17500

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 12.7 km from Phippsburg. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00170409 (Bath). Public domain.