Heyburn climate

Heyburn Frost Dates and Growing Season

NOAA 1991-2020 normals for Burley Muni AP, 1.9 km from Heyburn, elevation 4142 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Burley 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 May 7 and the first fall freeze around October 4, a growing season of about 150 days.

Median at 36°F
last May 24, first September 21
Median at 32°F
last May 7, first October 4
Median at 28°F
last April 21, first October 17

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 12Jun 6Jun 2May 29May 24May 20May 16May 12May 8
32°FMay 23May 15May 12May 9May 7May 4May 1Apr 28Apr 23
28°FMay 5May 1Apr 28Apr 24Apr 21Apr 18Apr 15Apr 12Apr 6
24°FApr 21Apr 16Apr 12Apr 7Apr 4Mar 31Mar 27Mar 20Mar 12
20°FApr 4Mar 28Mar 21Mar 15Mar 10Mar 7Mar 4Feb 28Feb 20
16°FMar 14Mar 7Mar 3Feb 28Feb 25Feb 20Feb 16Feb 11Feb 4

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 5Sep 10Sep 15Sep 18Sep 21Sep 24Sep 27Oct 1Oct 5
32°FSep 21Sep 26Sep 29Oct 1Oct 4Oct 7Oct 10Oct 14Oct 18
28°FOct 1Oct 6Oct 11Oct 14Oct 17Oct 20Oct 23Oct 26Nov 1
24°FOct 13Oct 19Oct 23Oct 26Oct 28Nov 1Nov 3Nov 7Nov 14
20°FOct 21Oct 28Nov 1Nov 5Nov 9Nov 13Nov 18Nov 22Nov 27
16°FOct 31Nov 6Nov 11Nov 16Nov 21Nov 24Nov 27Dec 1Dec 9

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°F14213312812411911410910394
32°F169163159154150146141136129
28°F198191185181176172168162155
24°F232223216211206201197190183
20°F266258251245239233228219209
16°F293283277271265259254248239

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
6,285
Cooling degree days, base 65°F
492
Growing degree days, base 40°F
4,473
Growing degree days, base 45°F
3,336
Growing degree days, base 50°F
2,381
Growing degree days, base 55°F
1,599
Growing degree days, base 60°F
973

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,11000
February88801
March73009
April536148
May29411210
June10861405
July10212666
August22174617
September16034332
October493186
November82406
December1,11100

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 1.9 km from Heyburn. 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 USW00024133 (Burley Muni AP). Public domain.