Cascade climate

Cascade Frost Dates and Growing Season

NOAA 1991-2020 normals for Hingham Wwtp, 8.1 km from Cascade, elevation 763 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hingham Wwtp. 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 3 and the first fall freeze around October 16, a growing season of about 165 days.

Median at 36°F
last May 15, first October 4
Median at 32°F
last May 3, first October 16
Median at 28°F
last April 20, 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 30May 26May 22May 18May 15May 12May 9May 5May 1
32°FMay 18May 13May 8May 5May 3Apr 30Apr 27Apr 24Apr 18
28°FMay 5Apr 30Apr 26Apr 23Apr 20Apr 17Apr 14Apr 10Apr 5
24°FApr 21Apr 17Apr 13Apr 10Apr 7Apr 5Apr 2Mar 31Mar 25
20°FApr 10Apr 6Apr 3Apr 1Mar 30Mar 26Mar 22Mar 19Mar 14
16°FApr 3Mar 30Mar 26Mar 22Mar 19Mar 17Mar 14Mar 11Mar 7

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 24Sep 28Sep 30Oct 2Oct 4Oct 7Oct 9Oct 13Oct 17
32°FOct 2Oct 7Oct 10Oct 13Oct 16Oct 19Oct 22Oct 25Oct 29
28°FOct 13Oct 18Oct 22Oct 25Oct 28Oct 30Nov 1Nov 4Nov 10
24°FOct 26Oct 30Nov 1Nov 4Nov 6Nov 9Nov 12Nov 16Nov 21
20°FNov 2Nov 7Nov 11Nov 14Nov 17Nov 20Nov 22Nov 26Dec 1
16°FNov 10Nov 16Nov 20Nov 22Nov 25Nov 28Dec 1Dec 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°F162155150147143139135130123
32°F184178173169165161157153145
28°F208201197193189185180174167
24°F232225220216212209204199194
20°F252246241236232228224219213
16°F270263258254249246241235228

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
7,417
Cooling degree days, base 65°F
491
Growing degree days, base 40°F
4,306
Growing degree days, base 45°F
3,281
Growing degree days, base 50°F
2,387
Growing degree days, base 55°F
1,618
Growing degree days, base 60°F
980

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,41300
February1,19300
March1,01409
April641240
May31716202
June8388456
July17188635
August22146589
September15248353
October495495
November85109
December1,22000

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 8.1 km from Cascade. 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 USC00473661 (Hingham Wwtp). Public domain.