Weber County climate

Weber County Frost Dates and Growing Season

NOAA 1991-2020 normals for Pineview Dam, 6.4 km from Weber County, elevation 4940 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Pineview 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 May 22 and the first fall freeze around September 26, a growing season of about 125 days.

Median at 36°F
last June 9, first September 14
Median at 32°F
last May 22, first September 26
Median at 28°F
last May 4, first October 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°FJun 24Jun 19Jun 15Jun 12Jun 9Jun 7Jun 2May 30May 24
32°FJun 8Jun 2May 30May 26May 22May 18May 15May 12May 7
28°FMay 20May 14May 10May 6May 4May 1Apr 29Apr 26Apr 21
24°FMay 3Apr 29Apr 25Apr 22Apr 19Apr 16Apr 12Apr 9Apr 4
20°FApr 18Apr 13Apr 9Apr 5Apr 2Mar 31Mar 28Mar 22Mar 15
16°FApr 5Mar 31Mar 27Mar 23Mar 18Mar 15Mar 11Mar 9Mar 5

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°FAug 31Sep 5Sep 8Sep 11Sep 14Sep 17Sep 20Sep 23Sep 28
32°FSep 11Sep 16Sep 20Sep 23Sep 26Sep 29Oct 1Oct 5Oct 9
28°FSep 23Sep 27Sep 30Oct 3Oct 6Oct 10Oct 13Oct 17Oct 22
24°FOct 1Oct 8Oct 14Oct 17Oct 19Oct 23Oct 25Oct 29Nov 3
20°FOct 16Oct 21Oct 25Oct 28Oct 31Nov 2Nov 6Nov 10Nov 16
16°FOct 26Nov 1Nov 4Nov 7Nov 11Nov 15Nov 19Nov 23Nov 26

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°F1181101051009693898377
32°F146139134129125121116110102
28°F172167162158154150146140131
24°F204196191186183178173168158
20°F234225219214209205201195187
16°F258249244239234230225218209

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
7,788
Cooling degree days, base 65°F
267
Growing degree days, base 40°F
3,655
Growing degree days, base 45°F
2,675
Growing degree days, base 50°F
1,857
Growing degree days, base 55°F
1,184
Growing degree days, base 60°F
651

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,37600
February1,12100
March92401
April662019
May4101124
June16622315
July23131573
August35102532
September23011251
October598040
November93802
December1,30500

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 6.4 km from Weber 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 USC00426869 (Pineview Dam). Public domain.