Spencer climate

Spencer Frost Dates and Growing Season

NOAA 1991-2020 normals for Worcester Rgnl AP, 10.2 km from Spencer, elevation 1000 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Worcester Rgnl AP. 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 23 and the first fall freeze around October 21, a growing season of about 181 days.

Median at 36°F
last May 4, first October 9
Median at 32°F
last April 23, first October 21
Median at 28°F
last April 11, first November 1

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

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 28Oct 1Oct 4Oct 6Oct 9Oct 12Oct 15Oct 18Oct 23
32°FOct 6Oct 10Oct 14Oct 18Oct 21Oct 24Oct 27Oct 30Nov 3
28°FOct 17Oct 23Oct 27Oct 30Nov 1Nov 3Nov 7Nov 11Nov 15
24°FOct 31Nov 3Nov 6Nov 9Nov 12Nov 15Nov 19Nov 23Nov 29
20°FNov 10Nov 14Nov 18Nov 22Nov 25Nov 28Dec 1Dec 4Dec 11
16°FNov 19Nov 25Nov 29Dec 1Dec 4Dec 6Dec 10Dec 15Dec 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°F175169165161158154150146139
32°F198193189184181177172167160
28°F222215211207205201197192185
24°F245238233229225221217212206
20°F265258253248244241237232226
16°F284277271267263259255249242

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
6,623
Cooling degree days, base 65°F
502
Growing degree days, base 40°F
4,553
Growing degree days, base 45°F
3,451
Growing degree days, base 50°F
2,494
Growing degree days, base 55°F
1,680
Growing degree days, base 60°F
1,013

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,24901
February1,06401
March94609
April570361
May27821231
June7884457
July12190643
August20153598
September13947362
October4513109
November744021
December1,07102

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 10.2 km from Spencer. 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 USW00094746 (Worcester Rgnl AP). Public domain.