Dighton climate

Dighton Frost Dates and Growing Season

NOAA 1991-2020 normals for Healy, 18.7 km from Dighton, elevation 2850 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Healy. 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 28 and the first fall freeze around October 15, a growing season of about 169 days.

Median at 36°F
last May 7, first October 6
Median at 32°F
last April 28, first October 15
Median at 28°F
last April 18, first October 23

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 14May 11May 9May 7May 5May 2Apr 30Apr 26
32°FMay 10May 5May 2Apr 30Apr 28Apr 26Apr 22Apr 19Apr 15
28°FMay 2Apr 28Apr 24Apr 21Apr 18Apr 15Apr 12Apr 9Apr 4
24°FApr 22Apr 17Apr 13Apr 10Apr 7Apr 4Apr 2Mar 30Mar 23
20°FApr 14Apr 8Apr 4Apr 2Mar 30Mar 25Mar 20Mar 14Mar 8
16°FApr 6Mar 31Mar 26Mar 21Mar 15Mar 11Mar 7Mar 4Feb 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 23Sep 28Oct 1Oct 4Oct 6Oct 8Oct 11Oct 15Oct 18
32°FOct 1Oct 5Oct 9Oct 13Oct 15Oct 17Oct 20Oct 22Oct 25
28°FOct 9Oct 15Oct 18Oct 20Oct 23Oct 26Oct 28Oct 31Nov 3
24°FOct 17Oct 22Oct 26Oct 29Oct 31Nov 2Nov 5Nov 9Nov 14
20°FOct 23Oct 29Nov 1Nov 4Nov 8Nov 11Nov 14Nov 19Nov 23
16°FOct 30Nov 5Nov 9Nov 13Nov 17Nov 21Nov 24Nov 28Dec 3

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°F168162158154151147143139132
32°F185180175172169165161156148
28°F206200195191187183179175167
24°F226219215210206202197192185
20°F248240233228224220214208199
16°F269260254247242237231226215

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
5,325
Cooling degree days, base 65°F
1,330
Growing degree days, base 40°F
6,205
Growing degree days, base 45°F
4,948
Growing degree days, base 50°F
3,841
Growing degree days, base 55°F
2,871
Growing degree days, base 60°F
2,036

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,07001
February87608
March678153
April4029153
May15480403
June17275708
July2425888
August4357818
September66162550
October33822219
November699037
December1,02002

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 18.7 km from Dighton. 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 USC00143554 (Healy). Public domain.