Frostproof Frost Dates and Growing Season

NOAA 1991-2020 normals for Avon Park 2 W, 16.8 km from Frostproof, elevation 154 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Avon Park 2 W. 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 January 28 and the first fall freeze around January 8, a growing season of about 343 days.

Median at 36°F: last February 10, first December 29
Median at 32°F: last January 28, first January 8
Median at 28°F: last January 14, first January 9

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	Mar 12	Mar 2	Feb 24	Feb 16	Feb 10	Feb 5	Jan 31	Jan 26	Jan 13
32°F	Feb 26	Feb 15	Feb 7	Feb 1	Jan 28	Jan 21	Jan 14	Jan 8	Dec 31
28°F	Feb 5	Jan 31	Jan 27	Jan 21	Jan 14	Jan 11	Jan 7	Jan 3	Dec 26
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	Nov 29	Dec 6	Dec 14	Dec 22	Dec 29	Jan 3	Jan 8	Jan 17	Jan 29
32°F	Dec 12	Dec 23	Dec 31	Jan 4	Jan 8	Jan 13	Jan 21	Jan 31	Feb 10
28°F	Dec 18	Dec 30	Jan 3	Jan 6	Jan 9	Jan 13	Jan 20	Jan 27	Feb 2
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	345	334	327	319	312	305	298	288	276
32°F	365	365	358	350	343	334	329	319	307
28°F	365	365	365	365	365	365	360	347	336
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: 97% of years
32°F or colder: 69% of years
28°F or colder: 32% of years
24°F or colder: 8% 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: 507
Cooling degree days, base 65°F: 3,578
Growing degree days, base 40°F: 12,197
Growing degree days, base 45°F: 10,379
Growing degree days, base 50°F: 8,577
Growing degree days, base 55°F: 6,817
Growing degree days, base 60°F: 5,139

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Cooling DD	Growing DD 50
January	176	55	361
February	100	78	402
March	55	139	550
April	12	240	678
May	1	396	860
June	0	490	940
July	0	539	1,004
August	0	552	1,017
September	0	487	937
October	6	351	811
November	40	157	568
December	119	94	448

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 16.8 km from Frostproof. 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 USC00080369 (Avon Park 2 W). Public domain.