Westfield climate

Westfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Presque Isle, 11.5 km from Westfield, elevation 599 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Presque Isle. 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 14 and the first fall freeze around September 26, a growing season of about 131 days.

Median at 36°F
last May 31, first September 15
Median at 32°F
last May 14, first September 26
Median at 28°F
last May 1, first October 6

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 17Jun 11Jun 6Jun 2May 31May 28May 25May 21May 14
32°FJun 1May 26May 22May 18May 14May 11May 7May 3Apr 30
28°FMay 16May 10May 6May 3May 1Apr 29Apr 27Apr 24Apr 20
24°FMay 2Apr 29Apr 27Apr 24Apr 22Apr 19Apr 16Apr 13Apr 8
20°FApr 24Apr 21Apr 18Apr 15Apr 12Apr 9Apr 7Apr 5Apr 2
16°FApr 17Apr 12Apr 9Apr 6Apr 4Apr 2Apr 1Mar 29Mar 24

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 1Sep 4Sep 8Sep 12Sep 15Sep 18Sep 21Sep 24Sep 28
32°FSep 10Sep 16Sep 20Sep 23Sep 26Sep 29Oct 2Oct 5Oct 9
28°FSep 21Sep 27Oct 1Oct 3Oct 6Oct 9Oct 13Oct 18Oct 25
24°FOct 1Oct 5Oct 10Oct 14Oct 18Oct 24Oct 29Nov 2Nov 6
20°FOct 9Oct 20Oct 28Nov 1Nov 3Nov 6Nov 9Nov 14Nov 19
16°FOct 29Nov 4Nov 8Nov 12Nov 15Nov 18Nov 20Nov 24Nov 28

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°F124119114110106101979183
32°F152145140135131128122116108
28°F178171165161157153148143136
24°F202195189185181177171165157
20°F223217213209204199195188179
16°F242235230226222218214208200

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
8,768
Cooling degree days, base 65°F
273
Growing degree days, base 40°F
3,611
Growing degree days, base 45°F
2,684
Growing degree days, base 50°F
1,876
Growing degree days, base 55°F
1,192
Growing degree days, base 60°F
647

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,61800
February1,38300
March1,21402
April767013
May3739154
June13445363
July36110539
August5784493
September23524258
October609150
November96004
December1,38400

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 11.5 km from Westfield. 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 USC00176937 (Presque Isle). Public domain.