Newport News climate

Newport News Frost Dates and Growing Season

NOAA 1991-2020 normals for Norfolk Nas, 13.5 km from Newport News, elevation 17 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Norfolk Nas. 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 16 and the first fall freeze around November 26, a growing season of about 255 days.

Median at 36°F
last March 29, first November 14
Median at 32°F
last March 16, first November 26
Median at 28°F
last March 2, first December 12

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 10Apr 6Apr 3Apr 1Mar 29Mar 27Mar 23Mar 19Mar 12
32°FApr 1Mar 27Mar 23Mar 19Mar 16Mar 13Mar 9Mar 5Feb 26
28°FMar 19Mar 14Mar 9Mar 5Mar 2Feb 27Feb 23Feb 16Feb 9
24°FMar 6Mar 1Feb 24Feb 20Feb 14Feb 9Feb 4Jan 31Jan 21
20°FFeb 26Feb 17Feb 10Feb 4Jan 31Jan 28Jan 22Jan 15Jan 6
16°FFeb 12Feb 2Jan 31Jan 28Jan 24Jan 20Jan 16Jan 9Jan 3

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°FNov 1Nov 4Nov 7Nov 11Nov 14Nov 17Nov 20Nov 24Nov 29
32°FNov 8Nov 14Nov 18Nov 23Nov 26Nov 29Dec 2Dec 8Dec 17
28°FNov 21Nov 29Dec 2Dec 7Dec 12Dec 19Dec 24Dec 31Jan 5
24°FDec 5Dec 14Dec 21Dec 27Jan 1Jan 4Jan 9Jan 16Jan 26
20°FDec 21Dec 30Jan 2Jan 6Jan 11Jan 16Jan 21Jan 27Feb 4
16°FJan 1Jan 5Jan 8Jan 13Jan 17Jan 20Jan 25Jan 30Feb 5

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°F253244238234230226222218212
32°F283272266260255251246239231
28°F311304297292286280274267258
24°F343331326319313307303296284
20°F365365353344335332326318307
16°F365365365365365359347337330

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
98% of years
20°F or colder
77% of years
16°F or colder
42% 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
3,106
Cooling degree days, base 65°F
1,823
Growing degree days, base 40°F
8,035
Growing degree days, base 45°F
6,466
Growing degree days, base 50°F
5,062
Growing degree days, base 55°F
3,819
Growing degree days, base 60°F
2,737

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January713136
February586144
March4628122
April20552313
May53153566
June5341786
July0485950
August0431896
September5268712
October11773424
November3678151
December594262

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 13.5 km from Newport News. 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 USW00013750 (Norfolk Nas). Public domain.