Manatee County Frost Dates and Growing Season

NOAA 1991-2020 normals for Parrish, 14.6 km from Manatee County, elevation 60 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Parrish. 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 9, a growing season of about 355 days.

Median at 36°F: last February 6, first January 2
Median at 32°F: last January 28, first January 9
Median at 28°F: last January 17, first January 14

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 4	Feb 26	Feb 20	Feb 12	Feb 6	Feb 1	Jan 28	Jan 17	Jan 4
32°F	Feb 24	Feb 15	Feb 6	Feb 2	Jan 28	Jan 19	Jan 11	Jan 6	Dec 31
28°F	Feb 14	Feb 4	Feb 1	Jan 29	Jan 17	Jan 12	Jan 9	Jan 5	Dec 31
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 2	Dec 10	Dec 21	Dec 28	Jan 2	Jan 6	Jan 14	Jan 22	Feb 4
32°F	Dec 18	Dec 27	Jan 1	Jan 5	Jan 9	Jan 15	Jan 23	Feb 1	Feb 13
28°F	Dec 29	Jan 2	Jan 6	Jan 9	Jan 14	Jan 20	Jan 29	Feb 1	Feb 7
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	360	343	334	328	320	313	306	299	287
32°F	365	365	365	364	355	344	333	326	313
28°F	365	365	365	365	365	365	365	360	341
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: 90% of years
32°F or colder: 59% of years
28°F or colder: 21% of years
24°F or colder: 4% 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: 513
Cooling degree days, base 65°F: 3,389
Growing degree days, base 40°F: 12,003
Growing degree days, base 45°F: 10,182
Growing degree days, base 50°F: 8,375
Growing degree days, base 55°F: 6,607
Growing degree days, base 60°F: 4,926

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Cooling DD	Growing DD 50
January	171	50	356
February	107	64	381
March	59	118	525
April	14	218	654
May	1	370	834
June	0	477	927
July	0	530	995
August	0	535	1,000
September	0	477	927
October	5	333	794
November	40	140	551
December	117	78	432

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 14.6 km from Manatee County. 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 USC00086880 (Parrish). Public domain.