Lincoln County climate

Lincoln County Frost Dates and Growing Season

NOAA 1991-2020 normals for Richfield, 5.7 km from Lincoln County, elevation 4309 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Richfield. 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 May 24 and the first fall freeze around September 26, a growing season of about 123 days.

Median at 36°F
last June 11, first September 14
Median at 32°F
last May 24, first September 26
Median at 28°F
last May 8, first October 7

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°FJun 27Jun 21Jun 17Jun 14Jun 11Jun 7Jun 4May 30May 23
32°FJun 14Jun 7Jun 1May 28May 24May 20May 16May 13May 6
28°FMay 28May 20May 16May 11May 8May 4May 1Apr 28Apr 23
24°FMay 10May 4May 1Apr 29Apr 25Apr 20Apr 17Apr 12Apr 4
20°FApr 30Apr 20Apr 15Apr 10Apr 5Apr 1Mar 28Mar 20Mar 13
16°FApr 6Mar 30Mar 24Mar 17Mar 13Mar 10Mar 6Mar 3Feb 25

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°FSep 1Sep 4Sep 8Sep 11Sep 14Sep 17Sep 20Sep 23Sep 27
32°FSep 10Sep 16Sep 20Sep 23Sep 26Sep 29Oct 1Oct 5Oct 10
28°FSep 23Sep 28Oct 1Oct 4Oct 7Oct 11Oct 14Oct 17Oct 22
24°FOct 5Oct 9Oct 14Oct 17Oct 20Oct 23Oct 26Oct 30Nov 3
20°FOct 16Oct 21Oct 25Oct 27Oct 30Nov 1Nov 5Nov 9Nov 15
16°FOct 25Oct 30Nov 2Nov 5Nov 10Nov 14Nov 18Nov 23Nov 29

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°F117109103989389857971
32°F14513713212712311811310697
28°F174167162157152148143137128
24°F201194189183178174170165156
20°F235226218213207201197191182
16°F263255249243236232226220210

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
100% of years
20°F or colder
100% of years
16°F or colder
100% 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
7,336
Cooling degree days, base 65°F
488
Growing degree days, base 40°F
4,097
Growing degree days, base 45°F
3,080
Growing degree days, base 50°F
2,223
Growing degree days, base 55°F
1,510
Growing degree days, base 60°F
929

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,30800
February1,05100
March87402
April617131
May3598166
June14554365
July21207651
August26181620
September18137319
October553167
November92902
December1,27100

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 5.7 km from Lincoln County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00107673 (Richfield). Public domain.