West Tisbury climate

West Tisbury Frost Dates and Growing Season

NOAA 1991-2020 normals for Vineyard Haven AP, 5.1 km from West Tisbury, elevation 68 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Vineyard Haven 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 May 7 and the first fall freeze around October 9, a growing season of about 156 days.

Median at 36°F
last May 21, first September 28
Median at 32°F
last May 7, first October 9
Median at 28°F
last April 26, first October 25

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 8Jun 3May 29May 25May 21May 16May 12May 8May 1
32°FMay 27May 20May 16May 11May 7May 3Apr 30Apr 26Apr 22
28°FMay 13May 5May 2Apr 29Apr 26Apr 23Apr 20Apr 16Apr 9
24°FApr 28Apr 22Apr 18Apr 14Apr 9Apr 6Apr 3Mar 31Mar 26
20°FApr 11Apr 6Apr 2Mar 31Mar 28Mar 24Mar 20Mar 15Mar 8
16°FMar 31Mar 26Mar 21Mar 16Mar 13Mar 10Mar 6Mar 1Feb 23

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 13Sep 18Sep 21Sep 24Sep 28Oct 1Oct 4Oct 7Oct 12
32°FSep 23Sep 29Oct 3Oct 6Oct 9Oct 13Oct 17Oct 22Oct 31
28°FOct 6Oct 13Oct 18Oct 21Oct 25Oct 30Nov 2Nov 5Nov 11
24°FOct 19Oct 26Nov 1Nov 3Nov 6Nov 10Nov 15Nov 21Nov 28
20°FNov 3Nov 8Nov 13Nov 18Nov 23Nov 27Dec 1Dec 5Dec 11
16°FNov 15Nov 23Nov 28Dec 2Dec 5Dec 10Dec 15Dec 20Dec 27

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°F154146140135130126121114106
32°F179170164160156151146140132
28°F207198192186182177171166158
24°F237229222216211206200195186
20°F267258251245240235230223214
16°F296286280274268262258250240

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
5,819
Cooling degree days, base 65°F
449
Growing degree days, base 40°F
4,670
Growing degree days, base 45°F
3,460
Growing degree days, base 50°F
2,441
Growing degree days, base 55°F
1,601
Growing degree days, base 60°F
932

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,04300
February92800
March86504
April578133
May3035189
June9152412
July17177625
August25158598
September12750375
October3696156
November605040
December87008

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 5.1 km from West Tisbury. 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 USW00094724 (Vineyard Haven AP). Public domain.