Riviera Beach Frost Dates and Growing Season

NOAA 1991-2020 normals for Juno Beach, 9.5 km from Riviera Beach, elevation 5 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Juno Beach. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

A freeze (32°F or colder) happens in only 13 percent of years at Juno Beach, so there is no typical freeze season.

Median at 36°F: last January 27, first January 16
Median at 32°F: last January 26, first January 16

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.

Threshold	10%	20%	30%	40%	50%	60%	70%	80%	90%
36°F	Feb 18	Feb 10	Feb 5	Jan 31	Jan 27	Jan 18	Jan 13	Jan 6	Jan 1
32°F	Feb 15	Feb 6	Feb 1	Jan 31	Jan 26	Jan 17	Jan 10	Jan 6	Jan 1
28°F	–	–	–	–	–	–	–	–	–
24°F	–	–	–	–	–	–	–	–	–
20°F	–	–	–	–	–	–	–	–	–
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.

Threshold	10%	20%	30%	40%	50%	60%	70%	80%	90%
36°F	Dec 26	Jan 1	Jan 5	Jan 10	Jan 16	Jan 23	Jan 30	Feb 3	Feb 11
32°F	Dec 27	Jan 1	Jan 6	Jan 10	Jan 16	Jan 28	Jan 31	Feb 2	Feb 12
28°F	–	–	–	–	–	–	–	–	–
24°F	–	–	–	–	–	–	–	–	–
20°F	–	–	–	–	–	–	–	–	–
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.

Threshold	10%	20%	30%	40%	50%	60%	70%	80%	90%
36°F	365	365	365	365	365	364	354	340	330
32°F	365	365	365	365	365	365	365	365	358
28°F	365	365	365	365	365	365	365	365	365
24°F	365	365	365	365	365	365	365	365	365
20°F	365	365	365	365	365	365	365	365	365
16°F	365	365	365	365	365	365	365	365	365

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder: 36% of years
32°F or colder: 13% of years
28°F or colder: 1% of years
24°F or colder: 0% of years
20°F or colder: 0% of years
16°F or colder: 0% 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: 231
Cooling degree days, base 65°F: 4,269
Growing degree days, base 40°F: 13,164
Growing degree days, base 45°F: 11,340
Growing degree days, base 50°F: 9,521
Growing degree days, base 55°F: 7,716
Growing degree days, base 60°F: 5,952

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Cooling DD	Growing DD 50
January	84	119	506
February	52	130	499
March	28	198	636
April	3	303	750
May	0	420	885
June	0	513	963
July	0	580	1,045
August	0	583	1,048
September	0	525	975
October	2	442	905
November	11	271	710
December	52	185	600

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 9.5 km from Riviera Beach. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00084461 (Juno Beach). Public domain.