Lee County climate

Lee County Frost Dates and Growing Season

NOAA 1991-2020 normals for Crisp CO Pwr Dam, 20.3 km from Lee County, elevation 245 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Crisp CO Pwr Dam. 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 9 and the first fall freeze around November 20, a growing season of about 258 days.

Median at 36°F
last March 23, first November 8
Median at 32°F
last March 9, first November 20
Median at 28°F
last February 23, first December 6

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 7Apr 2Mar 30Mar 27Mar 23Mar 19Mar 15Mar 9Mar 3
32°FMar 27Mar 21Mar 17Mar 13Mar 9Mar 5Mar 1Feb 25Feb 16
28°FMar 17Mar 10Mar 5Feb 28Feb 23Feb 17Feb 11Feb 3Jan 27
24°FMar 5Feb 24Feb 14Feb 8Feb 2Jan 30Jan 23Jan 17Jan 5
20°FFeb 19Feb 7Feb 1Jan 29Jan 23Jan 17Jan 11Jan 4Dec 28
16°FFeb 10Feb 2Jan 30Jan 26Jan 17Jan 14Jan 6Jan 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 27Nov 1Nov 3Nov 5Nov 8Nov 12Nov 15Nov 19Nov 27
32°FNov 4Nov 9Nov 13Nov 17Nov 20Nov 25Nov 30Dec 3Dec 13
28°FNov 15Nov 23Nov 27Dec 1Dec 6Dec 12Dec 22Jan 1Jan 8
24°FNov 29Dec 6Dec 12Dec 23Dec 30Jan 3Jan 8Jan 15Jan 29
20°FDec 10Dec 24Dec 30Jan 3Jan 7Jan 13Jan 18Jan 25Feb 1
16°FDec 18Dec 29Jan 1Jan 6Jan 14Jan 18Jan 25Jan 30Feb 5

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°F259248243237232227222217211
32°F289277270264258253247240232
28°F323313303296288281274266254
24°F362347336330323316307298286
20°F365365365365355345334329316
16°F365365365365365365365358336

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
91% of years
20°F or colder
60% of years
16°F or colder
22% 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
2,055
Cooling degree days, base 65°F
2,369
Growing degree days, base 40°F
9,495
Growing degree days, base 45°F
7,786
Growing degree days, base 50°F
6,198
Growing degree days, base 55°F
4,757
Growing degree days, base 60°F
3,471

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January534294
February3925116
March24026277
April8285456
May10271727
June0441891
July0525990
August0507972
September1357805
October64123526
November27320223
December4605121

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 20.3 km from Lee County. 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 USC00092361 (Crisp CO Pwr Dam). Public domain.