Townsend climate

Townsend Frost Dates and Growing Season

NOAA 1991-2020 normals for Fitchburg Coop, 9.7 km from Townsend, elevation 665 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Fitchburg Coop. 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 1 and the first fall freeze around October 9, a growing season of about 162 days.

Median at 36°F
last May 12, first October 1
Median at 32°F
last May 1, first October 9
Median at 28°F
last April 18, first October 21

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 26May 22May 19May 16May 12May 9May 6May 3Apr 30
32°FMay 14May 9May 6May 3May 1Apr 28Apr 26Apr 23Apr 19
28°FMay 1Apr 27Apr 23Apr 20Apr 18Apr 15Apr 12Apr 9Apr 5
24°FApr 18Apr 14Apr 9Apr 7Apr 4Apr 3Apr 1Mar 31Mar 25
20°FApr 6Apr 3Apr 1Mar 31Mar 29Mar 25Mar 21Mar 17Mar 12
16°FMar 31Mar 29Mar 26Mar 22Mar 19Mar 16Mar 13Mar 10Mar 6

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 17Sep 23Sep 26Sep 29Oct 1Oct 2Oct 5Oct 7Oct 11
32°FSep 29Oct 1Oct 5Oct 7Oct 9Oct 12Oct 16Oct 20Oct 26
28°FOct 5Oct 10Oct 13Oct 17Oct 21Oct 25Oct 30Nov 2Nov 7
24°FOct 17Oct 23Oct 29Nov 1Nov 4Nov 7Nov 11Nov 15Nov 22
20°FOct 31Nov 7Nov 11Nov 15Nov 19Nov 23Nov 27Dec 1Dec 7
16°FNov 18Nov 24Nov 28Dec 1Dec 2Dec 6Dec 9Dec 13Dec 19

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°F158152147144140137132128121
32°F181174169166162157154150144
28°F207199193189186181177172165
24°F236226221216212207203197191
20°F261253247242237232227221214
16°F280273268263260256250245238

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
6,760
Cooling degree days, base 65°F
427
Growing degree days, base 40°F
4,416
Growing degree days, base 45°F
3,343
Growing degree days, base 50°F
2,397
Growing degree days, base 55°F
1,603
Growing degree days, base 60°F
948

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,26900
February1,12800
March97600
April575032
May2709217
June4965466
July0178642
August11135589
September12140369
October485062
November774020
December1,10200

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 9.7 km from Townsend. 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 USC00192807 (Fitchburg Coop). Public domain.