Middletown climate

Middletown Frost Dates and Growing Season

NOAA 1991-2020 normals for Newport State AP, 1.6 km from Middletown, elevation 172 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Newport State 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 April 11 and the first fall freeze around November 4, a growing season of about 206 days.

Median at 36°F
last April 27, first October 24
Median at 32°F
last April 11, first November 4
Median at 28°F
last March 31, first November 16

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 8May 4May 1Apr 29Apr 27Apr 24Apr 22Apr 19Apr 15
32°FApr 24Apr 19Apr 16Apr 13Apr 11Apr 8Apr 6Apr 3Mar 31
28°FApr 10Apr 6Apr 4Apr 1Mar 31Mar 29Mar 26Mar 22Mar 17
24°FApr 1Mar 29Mar 26Mar 23Mar 20Mar 17Mar 15Mar 11Mar 7
20°FMar 26Mar 21Mar 17Mar 14Mar 11Mar 8Mar 4Mar 1Feb 24
16°FMar 17Mar 11Mar 7Mar 3Feb 28Feb 25Feb 20Feb 13Feb 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°FOct 10Oct 15Oct 18Oct 21Oct 24Oct 26Oct 29Nov 1Nov 6
32°FOct 22Oct 27Oct 30Nov 1Nov 4Nov 7Nov 9Nov 12Nov 17
28°FNov 2Nov 6Nov 10Nov 13Nov 16Nov 19Nov 22Nov 28Dec 2
24°FNov 13Nov 18Nov 23Nov 26Nov 29Dec 1Dec 3Dec 7Dec 13
20°FNov 25Dec 1Dec 3Dec 6Dec 9Dec 13Dec 17Dec 21Dec 28
16°FDec 4Dec 11Dec 16Dec 20Dec 23Dec 26Dec 31Jan 4Jan 13

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°F196190186183179176173168161
32°F223217213210206203199194187
28°F250243237233230226222218213
24°F274266262256252248244239233
20°F296288283278274270265260253
16°F322312306302297293287282273

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
5,520
Cooling degree days, base 65°F
574
Growing degree days, base 40°F
5,036
Growing degree days, base 45°F
3,798
Growing degree days, base 50°F
2,740
Growing degree days, base 55°F
1,855
Growing degree days, base 60°F
1,134

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,05100
February91300
March82906
April529144
May2638218
June5682476
July3215677
August5197657
September7565441
October3306175
November594039
December87307

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 1.6 km from Middletown. 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 USW00014787 (Newport State AP). Public domain.