Ucon climate

Ucon Frost Dates and Growing Season

NOAA 1991-2020 normals for Rigby, 9.8 km from Ucon, elevation 4856 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Rigby. 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 9 and the first fall freeze around October 5, a growing season of about 148 days.

Median at 36°F
last May 26, first September 24
Median at 32°F
last May 9, first October 5
Median at 28°F
last April 28, first October 16

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 14Jun 8Jun 4May 31May 26May 23May 19May 16May 10
32°FMay 25May 19May 15May 12May 9May 6May 3May 1Apr 27
28°FMay 11May 6May 2Apr 30Apr 28Apr 24Apr 21Apr 17Apr 12
24°FApr 30Apr 25Apr 19Apr 16Apr 13Apr 9Apr 6Apr 1Mar 24
20°FApr 17Apr 11Apr 6Apr 2Mar 30Mar 24Mar 17Mar 13Mar 8
16°FApr 1Mar 24Mar 16Mar 13Mar 9Mar 7Mar 5Mar 2Feb 27

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 9Sep 14Sep 19Sep 21Sep 24Sep 27Sep 30Oct 3Oct 6
32°FSep 21Sep 27Sep 30Oct 2Oct 5Oct 6Oct 10Oct 14Oct 18
28°FOct 2Oct 6Oct 9Oct 13Oct 16Oct 18Oct 21Oct 25Oct 28
24°FOct 11Oct 16Oct 20Oct 23Oct 25Oct 28Oct 31Nov 3Nov 9
20°FOct 21Oct 25Oct 29Nov 1Nov 4Nov 7Nov 11Nov 15Nov 21
16°FOct 29Nov 3Nov 6Nov 11Nov 14Nov 18Nov 22Nov 25Nov 29

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°F14013212712211811210710293
32°F167160156152148144139134125
28°F191183179174170167163158151
24°F217209204199195191186181174
20°F246237231226220215211205196
16°F269262255251246242237231220

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
7,311
Cooling degree days, base 65°F
383
Growing degree days, base 40°F
4,062
Growing degree days, base 45°F
3,024
Growing degree days, base 50°F
2,145
Growing degree days, base 55°F
1,412
Growing degree days, base 60°F
826

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,30800
February1,07600
March84705
April598028
May3435169
June14240352
July19160606
August24145586
September16832327
October551170
November92603
December1,30800

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 9.8 km from Ucon. 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 USC00107689 (Rigby). Public domain.