Brunswick climate

Brunswick Frost Dates and Growing Season

NOAA 1991-2020 normals for Brunswick, 0.3 km from Brunswick, elevation 662 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Brunswick. 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 April 10 and the first fall freeze around October 29, a growing season of about 201 days.

Median at 36°F
last April 21, first October 19
Median at 32°F
last April 10, first October 29
Median at 28°F
last March 31, first November 7

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°FMay 7May 2Apr 29Apr 25Apr 21Apr 18Apr 15Apr 11Apr 6
32°FApr 26Apr 22Apr 17Apr 13Apr 10Apr 7Apr 3Mar 31Mar 24
28°FApr 16Apr 10Apr 6Apr 3Mar 31Mar 28Mar 23Mar 19Mar 12
24°FApr 5Mar 31Mar 26Mar 22Mar 18Mar 15Mar 12Mar 7Mar 2
20°FMar 28Mar 20Mar 16Mar 13Mar 9Mar 6Mar 3Feb 28Feb 21
16°FMar 18Mar 13Mar 9Mar 6Mar 3Feb 28Feb 25Feb 19Feb 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°FOct 3Oct 10Oct 14Oct 16Oct 19Oct 22Oct 24Oct 27Oct 31
32°FOct 15Oct 21Oct 24Oct 27Oct 29Oct 31Nov 2Nov 5Nov 11
28°FOct 26Nov 1Nov 2Nov 5Nov 7Nov 10Nov 13Nov 17Nov 24
24°FNov 3Nov 7Nov 10Nov 14Nov 17Nov 21Nov 25Nov 30Dec 4
20°FNov 9Nov 15Nov 19Nov 23Nov 27Dec 1Dec 4Dec 8Dec 14
16°FNov 17Nov 24Nov 29Dec 1Dec 5Dec 9Dec 14Dec 18Dec 23

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°F197191186182179174170164158
32°F223215210205201196193186179
28°F246238233227223219214209202
24°F267259253248243238234227219
20°F286277271266261255250244235
16°F304295289284279274269263254

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
5,235
Cooling degree days, base 65°F
1,311
Growing degree days, base 40°F
6,336
Growing degree days, base 45°F
5,073
Growing degree days, base 50°F
3,937
Growing degree days, base 55°F
2,930
Growing degree days, base 60°F
2,054

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,15302
February91409
March675466
April34818187
May11895445
June10272712
July1396860
August3339801
September62156546
October29529248
November647254
December1,01006

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 0.3 km from Brunswick. 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 USC00231037 (Brunswick). Public domain.