Whitfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Sarasota Bradenton AP, 1.4 km from Whitfield, elevation 28 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sarasota Bradenton AP. 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 31 percent of years at Sarasota Bradenton AP, so there is no typical freeze season.

Median at 36°F: last January 27, first January 7
Median at 32°F: last January 15, first January 10

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 24	Feb 13	Feb 5	Feb 1	Jan 27	Jan 21	Jan 15	Jan 9	Jan 1
32°F	Feb 8	Feb 1	Jan 27	Jan 20	Jan 15	Jan 11	Jan 7	Jan 2	Dec 29
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 16	Dec 25	Dec 31	Jan 4	Jan 7	Jan 12	Jan 19	Jan 27	Feb 5
32°F	Dec 24	Dec 30	Jan 2	Jan 6	Jan 10	Jan 15	Jan 21	Jan 28	Feb 3
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	361	353	345	337	330	322	311
32°F	365	365	365	365	365	365	359	347	335
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: 70% of years
32°F or colder: 31% of years
28°F or colder: 5% 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: 394
Cooling degree days, base 65°F: 3,721
Growing degree days, base 40°F: 12,452
Growing degree days, base 45°F: 10,630
Growing degree days, base 50°F: 8,815
Growing degree days, base 55°F: 7,028
Growing degree days, base 60°F: 5,315

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Cooling DD	Growing DD 50
January	142	61	392
February	82	75	414
March	40	138	563
April	6	234	678
May	0	399	863
June	0	504	954
July	0	563	1,028
August	0	570	1,035
September	0	514	965
October	3	384	846
November	27	178	602
December	96	102	475

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 1.4 km from Whitfield. 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 USW00012871 (Sarasota Bradenton AP). Public domain.