Florence climate

Florence Frost Dates and Growing Season

NOAA 1991-2020 normals for Florence Rgnl AP, 3.8 km from Florence, elevation 146 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Florence Rgnl AP. 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 March 19 and the first fall freeze around November 13, a growing season of about 241 days.

Median at 36°F
last April 1, first November 4
Median at 32°F
last March 19, first November 13
Median at 28°F
last March 4, first November 27

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.

Threshold10%20%30%40%50%60%70%80%90%
36°FApr 16Apr 11Apr 7Apr 4Apr 1Mar 28Mar 24Mar 19Mar 14
32°FApr 5Mar 31Mar 27Mar 23Mar 19Mar 16Mar 11Mar 6Feb 28
28°FMar 26Mar 18Mar 12Mar 8Mar 4Feb 28Feb 24Feb 16Feb 6
24°FMar 13Mar 5Feb 28Feb 22Feb 15Feb 8Feb 1Jan 27Jan 14
20°FFeb 28Feb 18Feb 7Jan 31Jan 27Jan 19Jan 13Jan 6Dec 30
16°FFeb 8Jan 31Jan 27Jan 20Jan 16Jan 12Jan 7Jan 2Dec 26

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.

Threshold10%20%30%40%50%60%70%80%90%
36°FOct 23Oct 27Oct 30Nov 1Nov 4Nov 6Nov 9Nov 12Nov 18
32°FNov 1Nov 5Nov 8Nov 11Nov 13Nov 17Nov 21Nov 27Dec 2
28°FNov 9Nov 14Nov 18Nov 22Nov 27Dec 1Dec 4Dec 11Dec 23
24°FNov 21Nov 28Dec 3Dec 7Dec 15Dec 23Dec 31Jan 5Jan 14
20°FDec 3Dec 11Dec 19Dec 28Jan 1Jan 7Jan 13Jan 18Feb 1
16°FDec 14Dec 24Jan 1Jan 4Jan 8Jan 13Jan 17Jan 24Feb 1

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.

Threshold10%20%30%40%50%60%70%80%90%
36°F240232227222217214210205198
32°F267257251246241236231225218
28°F303291282276269263257250241
24°F342330320311305297289280266
20°F365365354346338332323312301
16°F365365365365365361352343331

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
100% of years
24°F or colder
98% of years
20°F or colder
82% of years
16°F or colder
42% 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
2,334
Cooling degree days, base 65°F
2,257
Growing degree days, base 40°F
9,140
Growing degree days, base 45°F
7,466
Growing degree days, base 50°F
5,926
Growing degree days, base 55°F
4,539
Growing degree days, base 60°F
3,312

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January575381
February4356103
March29324239
April10486436
May17240688
June1424873
July0533998
August0491956
September5323768
October89104483
November31017201
December5076102

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 3.8 km from Florence. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USW00013744 (Florence Rgnl AP). Public domain.