Stoneham climate

Stoneham Frost Dates and Growing Season

NOAA 1991-2020 normals for Reading, 5.3 km from Stoneham, elevation 110 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Reading. 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 25 and the first fall freeze around October 17, a growing season of about 174 days.

Median at 36°F
last May 7, first October 6
Median at 32°F
last April 25, first October 17
Median at 28°F
last April 11, first October 30

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

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 26Sep 30Oct 1Oct 4Oct 6Oct 8Oct 11Oct 15Oct 20
32°FOct 3Oct 7Oct 11Oct 14Oct 17Oct 20Oct 23Oct 28Nov 1
28°FOct 14Oct 20Oct 24Oct 27Oct 30Nov 1Nov 3Nov 6Nov 11
24°FOct 29Nov 1Nov 4Nov 7Nov 10Nov 12Nov 16Nov 20Nov 26
20°FNov 8Nov 13Nov 16Nov 20Nov 23Nov 26Nov 30Dec 3Dec 10
16°FNov 21Nov 26Nov 30Dec 1Dec 4Dec 7Dec 12Dec 17Dec 24

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°F168162158154151148144139134
32°F193187182179174170167163156
28°F219213209204201196192186179
24°F244238233228225221216211205
20°F269261255251246242239234228
16°F290282277273268263258253246

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
5,936
Cooling degree days, base 65°F
719
Growing degree days, base 40°F
5,066
Growing degree days, base 45°F
3,894
Growing degree days, base 50°F
2,875
Growing degree days, base 55°F
2,007
Growing degree days, base 60°F
1,290

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,14502
February97902
March858114
April509577
May23529270
June55122518
July5260721
August8219676
September10976419
October3897143
November668031
December97804

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 5.3 km from Stoneham. 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 USC00196783 (Reading). Public domain.