Florence climate

Florence Frost Dates and Growing Season

NOAA 1991-2020 normals for Georgetown Lake, 19.6 km from Florence, elevation 874 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Georgetown Lake. 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 6 and the first fall freeze around November 24, a growing season of about 259 days.

Median at 36°F
last March 22, first November 13
Median at 32°F
last March 6, first November 24
Median at 28°F
last February 23, first December 5

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 10Apr 4Mar 31Mar 27Mar 22Mar 18Mar 13Mar 7Mar 1
32°FMar 30Mar 22Mar 15Mar 11Mar 6Mar 3Feb 28Feb 22Feb 13
28°FMar 16Mar 9Mar 4Feb 28Feb 23Feb 17Feb 11Feb 2Jan 24
24°FMar 6Feb 27Feb 19Feb 10Feb 3Jan 29Jan 21Jan 13Dec 31
20°FFeb 25Feb 13Feb 3Jan 28Jan 19Jan 11Jan 6Dec 31Dec 21
16°FFeb 9Feb 2Jan 27Jan 18Jan 11Jan 6Jan 3Jan 1Dec 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 31Nov 3Nov 6Nov 9Nov 13Nov 16Nov 20Nov 25Dec 1
32°FNov 5Nov 10Nov 16Nov 20Nov 24Nov 27Dec 1Dec 5Dec 10
28°FNov 15Nov 22Nov 27Dec 1Dec 5Dec 9Dec 14Dec 22Jan 1
24°FNov 27Dec 4Dec 10Dec 16Dec 22Dec 28Jan 3Jan 11Jan 27
20°FDec 11Dec 19Dec 26Jan 1Jan 3Jan 8Jan 16Jan 26Feb 7
16°FDec 19Dec 28Jan 1Jan 3Jan 6Jan 11Jan 19Jan 30Feb 4

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°F261250244239232228222216209
32°F289278271265259254249242231
28°F321309302296288281275268258
24°F360346338331323315306298284
20°F365365365365357348340331314
16°F365365365365365365365359345

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
93% of years
20°F or colder
65% of years
16°F or colder
28% 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
1,949
Cooling degree days, base 65°F
2,748
Growing degree days, base 40°F
9,995
Growing degree days, base 45°F
8,282
Growing degree days, base 50°F
6,670
Growing degree days, base 55°F
5,202
Growing degree days, base 60°F
3,891

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January522388
February36410143
March21540316
April70112494
May9301756
June0473922
July05911,056
August06011,066
September3402849
October53179593
November24133276
December4725111

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 19.6 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 USC00413507 (Georgetown Lake). Public domain.