Frost dates / Oregon / Corvallis

Frost dates in Corvallis, OR

The station on this page is CORVALLIS STATE UNIV, OR US (USC00351862), 6.2 miles from the city point. Population in the Census 2024 estimate is 61,993.

Zone 8bUSDA average annual extreme minimum 15°F to 20°F, from ZIP 97331 (0.5 miles from the city point used on this page).

Median last 32°F is April 17. Median first 32°F is October 28. The 50% growing-season length is 194 days. The green band runs from the median last frost to the median first frost. Thin ticks mark the 10%, 50%, and 90% dates.

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Last 32°F in spring

NCEI’s probability is the chance the last spring minimum of 32°F or lower occurs on or after the date.

Probability	Date	How to read it
90%	March 22	Earlier date. A last 32°F on or after this day is common.
50%	April 17	Median.
10%	May 8	Later date. A last 32°F on or after this day is uncommon.

First 32°F in fall

NCEI’s probability is the chance the first autumn minimum of 32°F or lower occurs on or before the date.

Probability	Date	How to read it
10%	October 5	Earlier date. A first 32°F on or before this day is uncommon.
50%	October 28	Median.
90%	November 19	Later date. A first 32°F on or before this day is common.

32°F growing-season length

Days between the last spring 32°F and the first autumn 32°F. The figure is a length the season meets or exceeds at that probability, from NCEI, not a subtraction done on this site.

Probability the season is at least this long	Days
10%	227
50%	194
90%	163

28°F threshold

	10%	50%	90%
Last, on or after	April 5	March 1	January 25
First, on or before	October 22	November 17	December 18
Season at least	301 days	259 days	216 days

36°F threshold

	10%	50%	90%
Last, on or after	June 2	May 11	April 25
First, on or before	September 23	October 10	October 28
Season at least	176 days	151 days	122 days

Station CORVALLIS STATE UNIV, OR US (USC00351862). Completeness flag S, 27 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 100%. Freeze dates are conditional on that threshold occurring. Elevation 68.6 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

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Corvallis, OR

Zone 8bAverage annual extreme minimum 15°F to 20°F

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Oregon. Nearest qualified station: CORVALLIS STATE UNIV, OR US (USC00351862), 6.2 miles. Median last 32°F April 17. Median first 32°F October 28. The 50% growing-season length is 194 days.

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32°F probabilities at this station

	10%	50%	90%
Last 32°F on or after	May 8	April 17	March 22
First 32°F on or before	October 5	October 28	November 19

Column order matches the NCEI file: for the last freeze, 10% is the later date and 90% is the earlier date. How to read the probabilities.

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Planting calendar

Frost dates for Oregon are above. Planting windows appear for states with a cited extension guide. The fall and seed tools use the numbers you enter and the station dates.

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