Duval County climate

Duval County Frost Dates and Growing Season

NOAA 1991-2020 normals for Freer, 23.8 km from Duval County, elevation 562 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Freer. 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 February 10 and the first fall freeze around December 7, a growing season of about 304 days.

Median at 36°F
last March 1, first November 26
Median at 32°F
last February 10, first December 7
Median at 28°F
last January 21, first December 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°FMar 25Mar 15Mar 9Mar 5Mar 1Feb 24Feb 19Feb 12Feb 1
32°FMar 8Mar 1Feb 24Feb 17Feb 10Feb 3Jan 29Jan 22Jan 9
28°FFeb 23Feb 9Feb 2Jan 28Jan 21Jan 14Jan 6Dec 30Dec 17
24°FFeb 4Jan 27Jan 21Jan 14Jan 7Jan 2Dec 31Dec 24Dec 16
20°FJan 24Jan 20Jan 13Jan 7Jan 4Jan 1Dec 31Dec 26Dec 17
16°F–––––––––

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 8Nov 15Nov 19Nov 23Nov 26Nov 29Dec 3Dec 7Dec 15
32°FNov 18Nov 25Nov 29Dec 3Dec 7Dec 11Dec 16Dec 25Jan 4
28°FNov 28Dec 6Dec 9Dec 16Dec 21Dec 29Jan 3Jan 10Jan 28
24°FDec 8Dec 16Dec 21Dec 28Jan 1Jan 3Jan 6Jan 12Jan 22
20°FDec 15Dec 21Dec 28Dec 31Jan 1Jan 3Jan 6Jan 11Jan 18
16°F–––––––––

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°F303292284277271265259251238
32°F340329318310304297290281271
28°F365364355347340334328317304
24°F365365365365365363354345334
20°F365365365365365365365365357
16°F365365365365365365365365365

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
98% of years
28°F or colder
83% of years
24°F or colder
46% of years
20°F or colder
17% of years
16°F or colder
5% 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
1,112
Cooling degree days, base 65°F
3,601
Growing degree days, base 40°F
11,633
Growing degree days, base 45°F
9,849
Growing degree days, base 50°F
8,122
Growing degree days, base 55°F
6,487
Growing degree days, base 60°F
4,972

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January33921209
February19948296
March96132509
April24240667
May2437901
June05561,006
July06361,101
August06461,111
September1464914
October24291732
November13498428
December29432249

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 23.8 km from Duval 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 USC00413341 (Freer). Public domain.