Pendleton climate

Pendleton Frost Dates and Growing Season

NOAA 1991-2020 normals for Pendleton WFO, 5.3 km from Pendleton, elevation 1510 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Pendleton WFO. 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 14 and the first fall freeze around October 22, a growing season of about 188 days.

Median at 36°F
last May 2, first October 10
Median at 32°F
last April 14, first October 22
Median at 28°F
last March 23, first November 2

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 19May 13May 9May 6May 2Apr 29Apr 26Apr 23Apr 17
32°FMay 5Apr 29Apr 24Apr 18Apr 14Apr 9Apr 5Mar 31Mar 24
28°FApr 13Apr 5Mar 31Mar 28Mar 23Mar 18Mar 12Mar 8Mar 3
24°FMar 22Mar 14Mar 8Mar 4Mar 1Feb 26Feb 22Feb 17Feb 10
20°FMar 5Feb 28Feb 24Feb 20Feb 15Feb 10Feb 5Jan 29Jan 11
16°FFeb 28Feb 21Feb 14Feb 7Feb 2Jan 25Jan 16Jan 7Dec 27

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 5Oct 7Oct 10Oct 14Oct 17Oct 20Oct 25
32°FOct 7Oct 12Oct 16Oct 19Oct 22Oct 25Oct 28Oct 31Nov 5
28°FOct 18Oct 23Oct 27Oct 31Nov 2Nov 5Nov 9Nov 14Nov 20
24°FOct 28Nov 1Nov 6Nov 10Nov 14Nov 18Nov 23Nov 27Dec 3
20°FNov 3Nov 10Nov 16Nov 21Nov 25Dec 1Dec 5Dec 12Dec 24
16°FNov 11Nov 20Nov 26Dec 1Dec 7Dec 14Dec 23Jan 1Jan 17

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°F181174168164160155150145137
32°F214205199194188183178172164
28°F251242236230225219213206197
24°F286275268262256250244238229
20°F324311300292285277270263253
16°F354339331323314305297287273

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
95% 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
5,101
Cooling degree days, base 65°F
767
Growing degree days, base 40°F
5,442
Growing degree days, base 45°F
4,102
Growing degree days, base 50°F
2,980
Growing degree days, base 55°F
2,067
Growing degree days, base 60°F
1,331

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January92404
February73904
March609028
April412194
May20730295
June7696470
July7289747
August7264722
September8781445
October3816146
November706019
December94505

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 5.3 km from Pendleton. 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 USC00356550 (Pendleton WFO). Public domain.