Readfield climate

Readfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Livermore Falls 1 E, 17.9 km from Readfield, elevation 380 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Livermore Falls 1 E. 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 11 and the first fall freeze around September 29, a growing season of about 138 days.

Median at 36°F
last May 23, first September 19
Median at 32°F
last May 11, first September 29
Median at 28°F
last April 30, first October 8

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 6Jun 1May 29May 26May 23May 21May 18May 15May 10
32°FMay 24May 19May 16May 13May 11May 8May 6May 2Apr 29
28°FMay 12May 7May 3May 1Apr 30Apr 27Apr 25Apr 22Apr 18
24°FApr 29Apr 25Apr 21Apr 19Apr 17Apr 14Apr 11Apr 8Apr 5
20°FApr 17Apr 13Apr 10Apr 7Apr 6Apr 4Apr 3Mar 31Mar 26
16°FApr 8Apr 5Apr 3Apr 1Mar 31Mar 28Mar 25Mar 21Mar 17

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 7Sep 11Sep 14Sep 16Sep 19Sep 21Sep 24Sep 26Sep 30
32°FSep 16Sep 20Sep 23Sep 26Sep 29Oct 1Oct 3Oct 6Oct 11
28°FSep 26Oct 1Oct 3Oct 6Oct 8Oct 12Oct 16Oct 20Oct 26
24°FOct 7Oct 11Oct 16Oct 20Oct 23Oct 26Oct 30Nov 2Nov 6
20°FOct 20Oct 26Oct 30Nov 1Nov 4Nov 7Nov 9Nov 12Nov 17
16°FNov 3Nov 7Nov 11Nov 13Nov 16Nov 18Nov 20Nov 23Nov 27

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°F13713012512111711311010699
32°F157152147143138135131126120
28°F181175170166162158154149141
24°F207200195191187184179173166
20°F228222218215211207204199192
16°F249241237233230227224219214

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
8,205
Cooling degree days, base 65°F
286
Growing degree days, base 40°F
3,714
Growing degree days, base 45°F
2,757
Growing degree days, base 50°F
1,929
Growing degree days, base 55°F
1,231
Growing degree days, base 60°F
675

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,48800
February1,30200
March1,14205
April716019
May3657152
June12646373
July26125564
August4682500
September23826259
October585151
November90505
December1,26800

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 17.9 km from Readfield. 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 USC00174745 (Livermore Falls 1 E). Public domain.