Davis County climate

Davis County Frost Dates and Growing Season

NOAA 1991-2020 normals for Farmington 3 Nw, 15.3 km from Davis County, elevation 4380 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Farmington 3 Nw. 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 April 19 and the first fall freeze around October 19, a growing season of about 181 days.

Median at 36°F
last May 3, first October 9
Median at 32°F
last April 19, first October 19
Median at 28°F
last April 1, first November 1

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

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°F175169164159155151147141133
32°F206198191186181176171166158
28°F236227223218213208202197187
24°F267258251246241235230223215
20°F293284278272267262257251240
16°F321311304298293287281274263

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
5,709
Cooling degree days, base 65°F
1,007
Growing degree days, base 40°F
5,441
Growing degree days, base 45°F
4,243
Growing degree days, base 50°F
3,216
Growing degree days, base 55°F
2,344
Growing degree days, base 60°F
1,615

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,11700
February85701
March685021
April472287
May23030286
June51164563
July1381845
August4327787
September82100473
October4014139
November746014
December1,06301

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 15.3 km from Davis 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 USC00422726 (Farmington 3 Nw). Public domain.