Millcreek climate

Millcreek Frost Dates and Growing Season

NOAA 1991-2020 normals for Salt Lake Triad Ctr, 9.5 km from Millcreek, elevation 4280 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Salt Lake Triad Ctr. 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 March 31 and the first fall freeze around November 8, a growing season of about 224 days.

Median at 36°F
last April 18, first October 28
Median at 32°F
last March 31, first November 8
Median at 28°F
last March 8, first November 18

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 9May 1Apr 26Apr 21Apr 18Apr 13Apr 8Apr 3Mar 28
32°FApr 19Apr 12Apr 7Apr 3Mar 31Mar 26Mar 19Mar 13Mar 7
28°FApr 2Mar 27Mar 15Mar 11Mar 8Mar 3Feb 28Feb 24Feb 17
24°FMar 10Mar 4Feb 28Feb 24Feb 19Feb 15Feb 11Feb 6Jan 31
20°FFeb 27Feb 19Feb 13Feb 7Feb 3Jan 31Jan 26Jan 17Jan 3
16°FFeb 13Feb 6Feb 1Jan 28Jan 22Jan 14Jan 7Dec 31Dec 20

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°FOct 12Oct 17Oct 22Oct 25Oct 28Oct 31Nov 3Nov 7Nov 13
32°FOct 23Oct 28Nov 1Nov 5Nov 8Nov 11Nov 15Nov 20Nov 25
28°FNov 1Nov 7Nov 11Nov 15Nov 18Nov 23Nov 26Dec 1Dec 6
24°FNov 11Nov 17Nov 21Nov 25Nov 29Dec 3Dec 7Dec 11Dec 17
20°FNov 19Nov 26Nov 30Dec 6Dec 11Dec 15Dec 20Dec 25Jan 3
16°FNov 28Dec 6Dec 14Dec 19Dec 25Dec 28Jan 2Jan 10Jan 24

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°F221211205199194188181176166
32°F254243236230224219212206195
28°F281274267262255249242234223
24°F312302295289284278272265252
20°F342332325318311304298291280
16°F365360352344337331325317307

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
98% of years
16°F or colder
85% 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
4,724
Cooling degree days, base 65°F
1,402
Growing degree days, base 40°F
6,437
Growing degree days, base 45°F
5,108
Growing degree days, base 50°F
3,943
Growing degree days, base 55°F
2,945
Growing degree days, base 60°F
2,105

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January97201
February73905
March551057
April37011153
May15567388
June29227649
July1486950
August2429893
September41161571
October29221234
November626040
December94803

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 9.5 km from Millcreek. 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 USC00427606 (Salt Lake Triad Ctr). Public domain.