Bertie County climate

Bertie County Frost Dates and Growing Season

NOAA 1991-2020 normals for Lewiston, 19.7 km from Bertie County, elevation 50 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lewiston. 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 March 29 and the first fall freeze around November 7, a growing season of about 223 days.

Median at 36°F
last April 9, first October 29
Median at 32°F
last March 29, first November 7
Median at 28°F
last March 16, first November 21

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°FApr 23Apr 18Apr 15Apr 11Apr 9Apr 6Apr 4Apr 1Mar 27
32°FApr 12Apr 7Apr 4Apr 1Mar 29Mar 27Mar 22Mar 18Mar 12
28°FApr 1Mar 28Mar 23Mar 19Mar 16Mar 12Mar 8Mar 2Feb 24
24°FMar 20Mar 13Mar 8Mar 4Feb 28Feb 24Feb 17Feb 10Feb 1
20°FMar 6Feb 28Feb 20Feb 13Feb 7Feb 1Jan 28Jan 21Jan 10
16°FFeb 22Feb 11Feb 3Jan 30Jan 26Jan 21Jan 17Jan 11Jan 1

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 16Oct 21Oct 24Oct 26Oct 29Oct 31Nov 2Nov 5Nov 9
32°FOct 27Oct 31Nov 2Nov 5Nov 7Nov 11Nov 14Nov 18Nov 25
28°FNov 4Nov 9Nov 13Nov 17Nov 21Nov 26Dec 1Dec 4Dec 11
24°FNov 16Nov 23Nov 30Dec 3Dec 6Dec 12Dec 19Dec 27Jan 6
20°FDec 2Dec 8Dec 15Dec 23Dec 29Jan 3Jan 9Jan 16Jan 23
16°FDec 13Dec 23Dec 30Jan 4Jan 10Jan 14Jan 18Jan 25Feb 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°F221214209205202198194190183
32°F246238232227223219215210205
28°F280270262256251246240235227
24°F317305296291283276270262253
20°F350337330323316309303295283
16°F365365362353344337332324312

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
96% of years
16°F or colder
76% 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
3,145
Cooling degree days, base 65°F
1,754
Growing degree days, base 40°F
7,958
Growing degree days, base 45°F
6,397
Growing degree days, base 50°F
4,996
Growing degree days, base 55°F
3,754
Growing degree days, base 60°F
2,674

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January712141
February569252
March43312145
April17958340
May50163578
June3346793
July0454919
August0409874
September13238675
October15160381
November4039140
December630358

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 19.7 km from Bertie County. 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 USC00314962 (Lewiston). Public domain.