Quincy climate

Quincy Frost Dates and Growing Season

NOAA 1991-2020 normals for Quincy Dam 21, 3.9 km from Quincy, elevation 483 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Quincy Dam 21. 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 8 and the first fall freeze around October 30, a growing season of about 204 days.

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

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

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°F200195191187183178174168161
32°F223215211207204200194188182
28°F245238232228224220216210204
24°F265258253247242238234228220
20°F286276270265260256251245238
16°F303295289283277272266260251

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
5,353
Cooling degree days, base 65°F
1,273
Growing degree days, base 40°F
6,222
Growing degree days, base 45°F
4,974
Growing degree days, base 50°F
3,861
Growing degree days, base 55°F
2,873
Growing degree days, base 60°F
2,005

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,17801
February93706
March719347
April35616182
May11892442
June11270709
July1385849
August2332795
September59149541
October30627233
November657151
December1,01205

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

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00117077 (Quincy Dam 21). Public domain.