Story climate

Story Frost Dates and Growing Season

NOAA 1991-2020 normals for Story, 1.5 km from Story, elevation 5168 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Story. 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 23, a growing season of about 120 days.

Median at 36°F
last June 7, first September 11
Median at 32°F
last May 24, first September 23
Median at 28°F
last May 8, first October 3

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 21Jun 17Jun 14Jun 11Jun 7Jun 4Jun 1May 30May 24
32°FJun 9Jun 3May 31May 27May 24May 21May 18May 15May 10
28°FMay 24May 19May 14May 11May 8May 5May 2Apr 30Apr 24
24°FMay 9May 5May 2Apr 30Apr 26Apr 23Apr 20Apr 16Apr 11
20°FMay 1Apr 26Apr 22Apr 18Apr 15Apr 12Apr 8Apr 5Mar 31
16°FApr 21Apr 17Apr 13Apr 9Apr 5Apr 2Mar 30Mar 25Mar 17

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 27Sep 1Sep 5Sep 8Sep 11Sep 13Sep 17Sep 20Sep 24
32°FSep 8Sep 12Sep 17Sep 20Sep 23Sep 25Sep 29Oct 2Oct 7
28°FSep 18Sep 24Sep 27Oct 1Oct 3Oct 5Oct 9Oct 13Oct 19
24°FSep 26Oct 1Oct 5Oct 9Oct 13Oct 16Oct 20Oct 25Oct 30
20°FOct 2Oct 10Oct 14Oct 19Oct 23Oct 27Nov 1Nov 3Nov 8
16°FOct 12Oct 18Oct 23Oct 28Nov 1Nov 4Nov 8Nov 13Nov 19

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°F1151091041009793888274
32°F141134129124120116112107100
28°F169161156151146142137132124
24°F192184178174170165160154146
20°F214205198194189184179174165
16°F232225218211207202197191184

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
8,014
Cooling degree days, base 65°F
225
Growing degree days, base 40°F
3,382
Growing degree days, base 45°F
2,428
Growing degree days, base 50°F
1,648
Growing degree days, base 55°F
1,026
Growing degree days, base 60°F
548

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,19500
February1,10301
March1,00304
April735019
May502192
June23118256
July50101516
August8087473
September29118227
October659154
November94407
December1,22100

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 1.5 km from Story. 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 USC00488626 (Story). Public domain.