Mulberry Frost Dates and Growing Season

NOAA 1991-2020 normals for Lakeland 2, 11.5 km from Mulberry, elevation 139 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lakeland 2. 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 26 and the first fall freeze around January 9, a growing season of about 349 days.

Median at 36°F: last February 8, first December 30
Median at 32°F: last January 26, first January 9
Median at 28°F: last January 17, first January 13

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 8	Feb 27	Feb 20	Feb 14	Feb 8	Feb 3	Jan 29	Jan 21	Jan 11
32°F	Feb 21	Feb 10	Feb 3	Jan 30	Jan 26	Jan 20	Jan 14	Jan 9	Jan 2
28°F	Feb 5	Jan 30	Jan 26	Jan 21	Jan 17	Jan 13	Jan 9	Jan 5	Dec 30
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 3	Dec 11	Dec 19	Dec 25	Dec 30	Jan 3	Jan 9	Jan 14	Jan 26
32°F	Dec 20	Dec 28	Jan 1	Jan 5	Jan 9	Jan 13	Jan 20	Jan 28	Feb 4
28°F	Dec 28	Jan 2	Jan 5	Jan 9	Jan 13	Jan 17	Jan 24	Jan 29	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	351	338	330	325	316	310	303	296	285
32°F	365	365	363	356	349	341	334	327	313
28°F	365	365	365	365	365	365	363	354	339
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: 96% of years
32°F or colder: 68% of years
28°F or colder: 28% of years
24°F or colder: 6% 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: 444
Cooling degree days, base 65°F: 3,723
Growing degree days, base 40°F: 12,405
Growing degree days, base 45°F: 10,584
Growing degree days, base 50°F: 8,776
Growing degree days, base 55°F: 7,004
Growing degree days, base 60°F: 5,306

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Cooling DD	Growing DD 50
January	152	64	389
February	89	89	423
March	47	151	569
April	8	256	698
May	0	409	874
June	0	504	954
July	0	563	1,028
August	0	567	1,032
September	0	501	951
October	4	358	818
November	35	161	576
December	109	101	464

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 11.5 km from Mulberry. 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 USC00084802 (Lakeland 2). Public domain.