Gridley climate

Gridley Frost Dates and Growing Season

NOAA 1991-2020 normals for Chenoa, 13.7 km from Gridley, elevation 719 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Chenoa. 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 23 and the first fall freeze around October 15, a growing season of about 174 days.

Median at 36°F
last May 3, first October 4
Median at 32°F
last April 23, first October 15
Median at 28°F
last April 12, first October 26

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 18May 13May 8May 5May 3Apr 30Apr 28Apr 25Apr 21
32°FMay 7May 2Apr 29Apr 25Apr 23Apr 21Apr 18Apr 14Apr 9
28°FApr 27Apr 23Apr 19Apr 16Apr 12Apr 8Apr 5Apr 2Mar 31
24°FApr 17Apr 11Apr 7Apr 4Apr 2Mar 31Mar 29Mar 24Mar 17
20°FApr 6Apr 2Mar 31Mar 28Mar 23Mar 20Mar 15Mar 11Mar 4
16°FMar 31Mar 26Mar 21Mar 17Mar 14Mar 11Mar 7Mar 2Feb 24

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 21Sep 25Sep 29Oct 1Oct 4Oct 7Oct 10Oct 13Oct 17
32°FSep 29Oct 5Oct 9Oct 12Oct 15Oct 18Oct 21Oct 23Oct 29
28°FOct 12Oct 17Oct 21Oct 24Oct 26Oct 29Oct 31Nov 3Nov 8
24°FOct 25Oct 30Nov 1Nov 3Nov 5Nov 8Nov 12Nov 16Nov 21
20°FNov 2Nov 6Nov 9Nov 12Nov 15Nov 18Nov 22Nov 25Dec 1
16°FNov 9Nov 14Nov 18Nov 21Nov 24Nov 27Dec 1Dec 4Dec 11

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°F172165161157152148145140133
32°F193187182178174170165161154
28°F217210205200197193188184177
24°F238232226221217214210206198
20°F260252247242237233229224217
16°F281272265260256251247241234

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
6,106
Cooling degree days, base 65°F
862
Growing degree days, base 40°F
5,430
Growing degree days, base 45°F
4,273
Growing degree days, base 50°F
3,234
Growing degree days, base 55°F
2,312
Growing degree days, base 60°F
1,515

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,28801
February1,04602
March807135
April4358128
May16269380
June22196624
July4266727
August10211666
September9197459
October37414180
November752031
December1,11602

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 13.7 km from Gridley. 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 USC00111475 (Chenoa). Public domain.