Pine Hills Frost Dates and Growing Season

NOAA 1991-2020 normals for Orlando W, 10.7 km from Pine Hills, elevation 150 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Orlando 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 9, a growing season of about 343 days.

Median at 36°F: last February 8, first December 27
Median at 32°F: last January 28, first January 9
Median at 28°F: last January 20, 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 12	Feb 28	Feb 23	Feb 16	Feb 8	Feb 4	Jan 31	Jan 22	Jan 10
32°F	Feb 26	Feb 16	Feb 8	Feb 2	Jan 28	Jan 21	Jan 14	Jan 8	Jan 1
28°F	Feb 13	Feb 6	Feb 1	Jan 27	Jan 20	Jan 15	Jan 10	Jan 7	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 1	Dec 6	Dec 14	Dec 21	Dec 27	Jan 1	Jan 6	Jan 13	Jan 24
32°F	Dec 18	Dec 27	Jan 1	Jan 5	Jan 9	Jan 15	Jan 21	Jan 29	Feb 6
28°F	Dec 25	Jan 1	Jan 6	Jan 9	Jan 13	Jan 18	Jan 26	Feb 3	Feb 10
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	336	329	320	313	306	298	289	278
32°F	365	365	358	349	343	336	330	322	309
28°F	365	365	365	365	365	365	360	348	334
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: 70% of years
28°F or colder: 29% 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: 573
Cooling degree days, base 65°F: 3,391
Growing degree days, base 40°F: 11,944
Growing degree days, base 45°F: 10,126
Growing degree days, base 50°F: 8,323
Growing degree days, base 55°F: 6,564
Growing degree days, base 60°F: 4,898

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Cooling DD	Growing DD 50
January	191	37	325
February	117	56	366
March	65	118	519
April	11	197	636
May	0	386	851
June	0	493	943
July	0	552	1,017
August	0	550	1,015
September	0	492	942
October	6	320	780
November	47	132	535
December	135	60	395

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 10.7 km from Pine Hills. 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 USC00086634 (Orlando W). Public domain.