Brewster Hill climate

Brewster Hill Frost Dates and Growing Season

NOAA 1991-2020 normals for Carmel 4N, 6.9 km from Brewster Hill, elevation 680 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Carmel 4N. 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 28 and the first fall freeze around October 16, a growing season of about 170 days.

Median at 36°F
last May 10, first October 5
Median at 32°F
last April 28, first October 16
Median at 28°F
last April 13, first October 28

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

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 25Sep 29Oct 1Oct 3Oct 5Oct 8Oct 10Oct 14Oct 19
32°FOct 3Oct 7Oct 10Oct 12Oct 16Oct 19Oct 22Oct 26Nov 1
28°FOct 12Oct 17Oct 21Oct 24Oct 28Nov 1Nov 3Nov 6Nov 11
24°FOct 25Oct 31Nov 3Nov 6Nov 9Nov 13Nov 16Nov 20Nov 25
20°FNov 7Nov 13Nov 16Nov 19Nov 22Nov 26Nov 29Dec 2Dec 8
16°FNov 19Nov 24Nov 28Dec 1Dec 3Dec 6Dec 9Dec 14Dec 21

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°F167160156152148144141137130
32°F189183178174170166162158151
28°F216209204200196192187182174
24°F242235229224221217213207201
20°F266259253248244241235230223
16°F288280275269264260255250244

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
6,574
Cooling degree days, base 65°F
405
Growing degree days, base 40°F
4,440
Growing degree days, base 45°F
3,333
Growing degree days, base 50°F
2,370
Growing degree days, base 55°F
1,554
Growing degree days, base 60°F
894

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,24900
February1,04401
March93309
April548365
May26915230
June7970442
July13153604
August27123561
September14840345
October459297
November746015
December1,05901

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 6.9 km from Brewster Hill. 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 USC00301211 (Carmel 4N). Public domain.