Oakridge climate

Oakridge Frost Dates and Growing Season

NOAA 1991-2020 normals for Oakridge Fish Hatchery, 1.6 km from Oakridge, elevation 1275 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Oakridge Fish Hatchery. 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 24 and the first fall freeze around October 24, a growing season of about 183 days.

Median at 36°F
last May 12, first October 2
Median at 32°F
last April 24, first October 24
Median at 28°F
last March 22, first November 13

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

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 11Sep 19Sep 24Sep 29Oct 2Oct 6Oct 11Oct 16Oct 22
32°FOct 2Oct 10Oct 16Oct 20Oct 24Oct 27Oct 31Nov 5Nov 13
28°FOct 24Oct 30Nov 4Nov 9Nov 13Nov 20Nov 28Dec 3Dec 13
24°FNov 9Nov 18Nov 29Dec 4Dec 9Dec 18Dec 24Jan 1Jan 16
20°FNov 29Dec 5Dec 10Dec 16Dec 22Dec 28Jan 1Jan 13Feb 1
16°FDec 6Dec 9Dec 13Dec 20Dec 23Dec 28Dec 31Jan 4Jan 19

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°F166158152147141136130123113
32°F212201194188183177171163154
28°F279267256247239231223214202
24°F353337327315307298290281265
20°F365365365365362352342333317
16°F365365365365365365365365349

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
94% of years
20°F or colder
56% of years
16°F or colder
17% 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
5,443
Cooling degree days, base 65°F
178
Growing degree days, base 40°F
4,187
Growing degree days, base 45°F
2,895
Growing degree days, base 50°F
1,883
Growing degree days, base 55°F
1,100
Growing degree days, base 60°F
528

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January84900
February68002
March642012
April500051
May3394159
June19215276
July5666476
August5369480
September15423322
October424198
November68705
December86800

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 1.6 km from Oakridge. 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 USC00356213 (Oakridge Fish Hatchery). Public domain.