Shields climate

Shields Frost Dates and Growing Season

NOAA 1991-2020 normals for Saginaw #3, 8.1 km from Shields, elevation 600 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Saginaw #3. 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 29 and the first fall freeze around October 21, a growing season of about 175 days.

Median at 36°F
last May 7, first October 9
Median at 32°F
last April 29, first October 21
Median at 28°F
last April 17, first November 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°FMay 23May 18May 14May 11May 7May 5May 2Apr 30Apr 26
32°FMay 13May 7May 4Apr 30Apr 29Apr 26Apr 23Apr 19Apr 14
28°FMay 1Apr 27Apr 23Apr 20Apr 17Apr 14Apr 10Apr 6Apr 2
24°FApr 19Apr 15Apr 11Apr 8Apr 5Apr 2Mar 31Mar 28Mar 22
20°FApr 9Apr 4Apr 2Mar 31Mar 28Mar 24Mar 21Mar 17Mar 13
16°FApr 1Mar 28Mar 23Mar 20Mar 18Mar 15Mar 13Mar 9Mar 3

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 27Oct 1Oct 3Oct 6Oct 9Oct 11Oct 14Oct 17Oct 22
32°FOct 5Oct 11Oct 15Oct 18Oct 21Oct 24Oct 27Oct 30Nov 2
28°FOct 20Oct 26Oct 30Nov 1Nov 3Nov 5Nov 8Nov 12Nov 16
24°FNov 3Nov 6Nov 9Nov 12Nov 14Nov 17Nov 20Nov 23Nov 29
20°FNov 9Nov 15Nov 18Nov 21Nov 24Nov 27Nov 30Dec 4Dec 11
16°FNov 18Nov 24Nov 28Dec 1Dec 3Dec 6Dec 10Dec 17Dec 23

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°F170165161157153148144139134
32°F194187183179175171167162155
28°F220213208204200196192187180
24°F245237231227223219215211206
20°F265258253248244239235229223
16°F285278273268263259254247239

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
6,750
Cooling degree days, base 65°F
690
Growing degree days, base 40°F
4,807
Growing degree days, base 45°F
3,725
Growing degree days, base 50°F
2,779
Growing degree days, base 55°F
1,958
Growing degree days, base 60°F
1,255

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,30300
February1,12701
March960112
April578365
May24839280
June44140546
July8234691
August12198651
September12469398
October4427120
November788015
December1,11601

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 8.1 km from Shields. 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 USC00207222 (Saginaw #3). Public domain.