Norwood climate

Norwood Frost Dates and Growing Season

NOAA 1991-2020 normals for Norwood, 0.5 km from Norwood, elevation 7020 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Norwood. 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 25 and the first fall freeze around October 1, a growing season of about 128 days.

Median at 36°F
last June 6, first September 24
Median at 32°F
last May 25, first October 1
Median at 28°F
last May 11, first October 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°FJun 23Jun 17Jun 13Jun 10Jun 6Jun 3May 31May 26May 21
32°FJun 13Jun 7Jun 2May 29May 25May 21May 17May 12May 7
28°FJun 2May 25May 20May 16May 11May 7May 4Apr 30Apr 25
24°FMay 19May 11May 5May 2Apr 30Apr 25Apr 21Apr 18Apr 11
20°FMay 3Apr 29Apr 23Apr 19Apr 16Apr 11Apr 6Apr 2Mar 26
16°FApr 21Apr 13Apr 7Apr 2Mar 29Mar 24Mar 19Mar 13Mar 8

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 8Sep 14Sep 18Sep 21Sep 24Sep 26Sep 28Oct 1Oct 5
32°FSep 14Sep 21Sep 25Sep 28Oct 1Oct 3Oct 5Oct 9Oct 14
28°FSep 22Sep 29Oct 1Oct 5Oct 8Oct 11Oct 15Oct 19Oct 23
24°FOct 1Oct 7Oct 11Oct 14Oct 18Oct 21Oct 24Oct 28Nov 1
20°FOct 12Oct 17Oct 21Oct 24Oct 28Oct 31Nov 3Nov 7Nov 13
16°FOct 22Oct 28Nov 1Nov 4Nov 7Nov 10Nov 14Nov 17Nov 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°F127120116111107102989385
32°F151144138133128123119113105
28°F170164159154150145140134124
24°F193184179175170165161155147
20°F218210203198193188183176167
16°F247239231225220213208201192

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
6,862
Cooling degree days, base 65°F
268
Growing degree days, base 40°F
4,010
Growing degree days, base 45°F
2,944
Growing degree days, base 50°F
2,044
Growing degree days, base 55°F
1,301
Growing degree days, base 60°F
708

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,20600
February97300
March82002
April604027
May3613153
June10046399
July12132586
August2374516
September17312299
October529060
November86703
December1,19500

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 0.5 km from Norwood. 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 USC00056012 (Norwood). Public domain.