Ogden climate

Ogden Frost Dates and Growing Season

NOAA 1991-2020 normals for Manhattan Muni AP, 3.6 km from Ogden, elevation 1057 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Manhattan Muni AP. 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 21 and the first fall freeze around October 16, a growing season of about 177 days.

Median at 36°F
last May 1, first October 6
Median at 32°F
last April 21, first October 16
Median at 28°F
last April 10, first October 25

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 14May 9May 6May 3May 1Apr 28Apr 25Apr 22Apr 17
32°FMay 6May 1Apr 28Apr 24Apr 21Apr 18Apr 15Apr 12Apr 8
28°FApr 26Apr 21Apr 17Apr 14Apr 10Apr 7Apr 4Apr 1Mar 26
24°FApr 18Apr 10Apr 6Apr 3Mar 31Mar 29Mar 24Mar 20Mar 13
20°FApr 5Mar 31Mar 27Mar 22Mar 19Mar 15Mar 12Mar 7Mar 2
16°FMar 26Mar 20Mar 15Mar 12Mar 8Mar 4Mar 2Feb 26Feb 21

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 23Sep 29Oct 1Oct 4Oct 6Oct 9Oct 12Oct 15Oct 18
32°FOct 1Oct 7Oct 10Oct 14Oct 16Oct 19Oct 21Oct 24Oct 29
28°FOct 12Oct 17Oct 20Oct 22Oct 25Oct 28Oct 31Nov 2Nov 6
24°FOct 21Oct 26Oct 29Nov 1Nov 3Nov 5Nov 9Nov 13Nov 18
20°FOct 29Nov 2Nov 5Nov 9Nov 12Nov 16Nov 20Nov 24Dec 1
16°FNov 4Nov 10Nov 15Nov 19Nov 24Nov 28Dec 1Dec 5Dec 11

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°F176170165162157154150146140
32°F196189184181177173169164157
28°F217210205201197193188182175
24°F240232226221217213209204196
20°F263255249243237232227221214
16°F285277271264259254248241232

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
5,104
Cooling degree days, base 65°F
1,490
Growing degree days, base 40°F
6,528
Growing degree days, base 45°F
5,255
Growing degree days, base 50°F
4,117
Growing degree days, base 55°F
3,110
Growing degree days, base 60°F
2,235

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,10301
February869010
March634469
April33119199
May113108464
June8307750
July1458922
August2388851
September60174565
October30630240
November664145
December1,01403

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 3.6 km from Ogden. 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 USW00003936 (Manhattan Muni AP). Public domain.