Glendale climate

Glendale Frost Dates and Growing Season

NOAA 1991-2020 normals for Sexton Summit, 15.8 km from Glendale, elevation 3832 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sexton Summit. 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 16 and the first fall freeze around October 30, a growing season of about 164 days.

Median at 36°F
last June 7, first October 9
Median at 32°F
last May 16, first October 30
Median at 28°F
last April 23, first November 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°FJun 25Jun 19Jun 15Jun 10Jun 7Jun 3May 31May 25May 16
32°FJun 7Jun 1May 27May 22May 16May 10May 2Apr 29Apr 23
28°FMay 17May 8May 1Apr 26Apr 23Apr 17Apr 10Apr 1Mar 23
24°FApr 21Apr 8Mar 31Mar 26Mar 18Mar 9Feb 26Feb 13Jan 20
20°FMar 20Mar 2Feb 22Feb 11Jan 27Jan 15Jan 6Dec 30Dec 12
16°FFeb 7Jan 26Jan 14Jan 9Jan 5Jan 1Dec 29Dec 15Dec 10

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 15Sep 27Oct 1Oct 6Oct 9Oct 14Oct 17Oct 24Nov 1
32°FOct 8Oct 15Oct 21Oct 25Oct 30Nov 2Nov 5Nov 9Nov 17
28°FOct 28Nov 3Nov 7Nov 11Nov 17Nov 22Nov 28Dec 2Dec 10
24°FNov 14Nov 23Nov 30Dec 4Dec 9Dec 15Dec 23Jan 3Jan 24
20°FDec 1Dec 8Dec 15Dec 25Jan 1Jan 5Jan 17Feb 1Feb 26
16°FDec 7Dec 12Dec 19Dec 30Jan 2Jan 5Jan 11Jan 23Jan 31

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°F15014113412812211611010389
32°F197186177170164158152144134
28°F247234225217211203196188175
24°F330306290278269260250240223
20°F365365365361348338324309293
16°F365365365365365365365365348

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
99% of years
20°F or colder
69% of years
16°F or colder
20% 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
6,116
Cooling degree days, base 65°F
275
Growing degree days, base 40°F
3,903
Growing degree days, base 45°F
2,746
Growing degree days, base 50°F
1,836
Growing degree days, base 55°F
1,134
Growing degree days, base 60°F
614

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January83106
February75004
March784011
April647137
May44311132
June27121224
July8985463
August8392475
September18955330
October44911130
November705022
December87402

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 15.8 km from Glendale. 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 USW00024235 (Sexton Summit). Public domain.