Early climate

Early Frost Dates and Growing Season

NOAA 1991-2020 normals for Sac City, 15.2 km from Early, elevation 1210 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sac City. 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 30 and the first fall freeze around October 6, a growing season of about 158 days.

Median at 36°F
last May 8, first September 28
Median at 32°F
last April 30, first October 6
Median at 28°F
last April 19, 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°FMay 21May 16May 13May 11May 8May 7May 4May 2Apr 28
32°FMay 11May 7May 4May 2Apr 30Apr 28Apr 24Apr 20Apr 15
28°FMay 2Apr 28Apr 25Apr 22Apr 19Apr 17Apr 13Apr 9Apr 5
24°FApr 23Apr 18Apr 14Apr 11Apr 9Apr 6Apr 3Mar 31Mar 25
20°FApr 16Apr 10Apr 6Apr 3Apr 1Mar 29Mar 25Mar 21Mar 15
16°FApr 7Apr 2Mar 30Mar 25Mar 22Mar 18Mar 15Mar 11Mar 7

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 16Sep 19Sep 22Sep 25Sep 28Sep 30Oct 3Oct 6Oct 10
32°FSep 23Sep 28Oct 1Oct 4Oct 6Oct 10Oct 12Oct 16Oct 20
28°FOct 4Oct 8Oct 12Oct 15Oct 17Oct 19Oct 22Oct 25Oct 30
24°FOct 15Oct 19Oct 22Oct 25Oct 28Oct 30Nov 1Nov 3Nov 8
20°FOct 23Oct 28Oct 31Nov 2Nov 4Nov 6Nov 9Nov 13Nov 18
16°FNov 1Nov 3Nov 6Nov 9Nov 12Nov 16Nov 19Nov 24Nov 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°F158153149144142138134129123
32°F179171167162158155151148142
28°F200193189184180176172167161
24°F220213207203200196192187179
20°F237230225222217212208203196
16°F256249243239233229225220212

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
7,371
Cooling degree days, base 65°F
683
Growing degree days, base 40°F
4,773
Growing degree days, base 45°F
3,717
Growing degree days, base 50°F
2,776
Growing degree days, base 55°F
1,950
Growing degree days, base 60°F
1,249

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,48500
February1,21901
March963015
April553479
May23938289
June36155569
July8239696
August21173617
September14566381
October4888118
November908013
December1,30700

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 15.2 km from Early. 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 USC00137312 (Sac City). Public domain.