Millsboro climate

Millsboro Frost Dates and Growing Season

NOAA 1991-2020 normals for Georgetown Sussex CO AP, 12.3 km from Millsboro, elevation 51 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Georgetown Sussex CO 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 4 and the first fall freeze around November 6, a growing season of about 217 days.

Median at 36°F
last April 16, first October 27
Median at 32°F
last April 4, first November 6
Median at 28°F
last March 23, first November 19

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 2Apr 26Apr 22Apr 19Apr 16Apr 14Apr 10Apr 6Apr 1
32°FApr 16Apr 13Apr 9Apr 6Apr 4Apr 1Mar 31Mar 27Mar 22
28°FApr 5Apr 1Mar 29Mar 26Mar 23Mar 20Mar 16Mar 11Mar 3
24°FMar 25Mar 20Mar 17Mar 13Mar 10Mar 6Mar 2Feb 27Feb 20
20°FMar 15Mar 8Mar 4Mar 1Feb 25Feb 20Feb 15Feb 9Feb 2
16°FMar 4Feb 27Feb 20Feb 13Feb 8Feb 3Jan 31Jan 27Jan 15

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 13Oct 18Oct 21Oct 24Oct 27Oct 29Nov 1Nov 3Nov 8
32°FOct 23Oct 28Oct 31Nov 2Nov 6Nov 9Nov 13Nov 16Nov 22
28°FNov 4Nov 8Nov 12Nov 15Nov 19Nov 23Nov 27Dec 1Dec 6
24°FNov 14Nov 21Nov 27Dec 1Dec 4Dec 7Dec 13Dec 19Dec 27
20°FDec 1Dec 6Dec 11Dec 16Dec 21Dec 27Jan 1Jan 5Jan 15
16°FDec 13Dec 22Dec 28Jan 1Jan 5Jan 10Jan 15Jan 23Jan 31

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°F211204200196191187183178170
32°F239230225221217213209205198
28°F268260254249244240236231223
24°F300290282276271267262256248
20°F326315309304299294288281271
16°F357342334329323316309304295

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
94% 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
4,070
Cooling degree days, base 65°F
1,396
Growing degree days, base 40°F
6,911
Growing degree days, base 45°F
5,486
Growing degree days, base 50°F
4,225
Growing degree days, base 55°F
3,124
Growing degree days, base 60°F
2,183

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January871016
February731020
March600367
April30125213
May10791451
June10267706
July0422886
August0363828
September24184611
October21438303
November478290
December735134

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 12.3 km from Millsboro. 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 USW00013764 (Georgetown Sussex CO AP). Public domain.