Jacksonville climate

Jacksonville Frost Dates and Growing Season

NOAA 1991-2020 normals for New River Mcaf, 7.4 km from Jacksonville, elevation 26 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for New River Mcaf. 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 23 and the first fall freeze around November 16, a growing season of about 240 days.

Median at 36°F
last April 2, first November 5
Median at 32°F
last March 23, first November 16
Median at 28°F
last March 8, first December 1

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 17Apr 12Apr 8Apr 5Apr 2Mar 31Mar 26Mar 22Mar 16
32°FApr 7Apr 3Mar 31Mar 26Mar 23Mar 18Mar 15Mar 10Mar 2
28°FMar 29Mar 23Mar 18Mar 14Mar 8Mar 3Feb 27Feb 21Feb 12
24°FMar 16Mar 6Feb 28Feb 23Feb 16Feb 10Feb 3Jan 28Jan 20
20°FFeb 28Feb 15Feb 6Jan 31Jan 28Jan 23Jan 17Jan 10Dec 31
16°FFeb 7Jan 31Jan 28Jan 23Jan 20Jan 16Jan 10Jan 4Dec 30

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 22Oct 27Oct 31Nov 1Nov 5Nov 8Nov 11Nov 16Nov 21
32°FNov 1Nov 5Nov 9Nov 12Nov 16Nov 20Nov 25Dec 1Dec 7
28°FNov 11Nov 17Nov 22Nov 28Dec 1Dec 5Dec 12Dec 21Dec 31
24°FNov 23Dec 1Dec 8Dec 14Dec 22Dec 28Jan 2Jan 9Jan 20
20°FDec 6Dec 17Dec 27Dec 31Jan 3Jan 9Jan 16Jan 21Feb 1
16°FDec 22Dec 31Jan 3Jan 8Jan 13Jan 16Jan 20Jan 24Feb 1

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°F241232227223218214209205198
32°F268259253245240235230225216
28°F302292283277271265258250241
24°F339330321312306300292283272
20°F365363353344338333324315304
16°F365365365365365364353344333

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
99% of years
20°F or colder
81% of years
16°F or colder
41% 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
2,497
Cooling degree days, base 65°F
2,022
Growing degree days, base 40°F
8,762
Growing degree days, base 45°F
7,106
Growing degree days, base 50°F
5,591
Growing degree days, base 55°F
4,231
Growing degree days, base 60°F
3,038

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January603270
February470586
March34316197
April13168393
May24193634
June1376825
July0493958
August0453918
September4301747
October9693465
November31417199
December5116100

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 7.4 km from Jacksonville. 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 USW00093727 (New River Mcaf). Public domain.