Frost dates 2026–2027

Frost dates for Cornelius, Oregon

Median (50% chance) dates of the last and first 32°F frost, from NOAA 1991–2020 climate normals at Forest Grove, 2.5 mi away (close match).

Last spring frostApr 16
First fall frostOct 26
192 frost-free days
Last spring frostApr 161 year in 10 after May 5
First fall frostOct 261 year in 10 by Oct 6
Growing season192 daysbetween median 32°F dates
Hardiness zoneZone 8b15 to 20°F average extreme low

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Will it freeze in Cornelius in the next 7 nights?

No overnight lows at or below 32°F are forecast in Cornelius during the next 7 nights in the available NWS frost forecast.

Tonight: forecast low 39°F. Above 36°F.

NWS forecast period: Thu, Nov 5, 6:00 PM PST to Fri, Nov 6, 6:00 AM PST.

No nights at or below 36°F in the National Weather Service forecast for the next 7 nights.

Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.

Frost and freeze probabilities

Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.

These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.

Average first hard freeze in Cornelius

The median first fall hard-freeze date (28°F) is November 11, from NOAA’s 1991–2020 Climate Normals at Forest Grove. This is the 50% probability date, not a forecast for this year.

TemperatureLast spring date
90% · 50% · 10% chance of a later freeze
First fall date
10% · 50% · 90% chance of an earlier freeze
Season
36°F frost possible Apr 19 · May 4 · May 25 Sep 24 · Oct 8 · Oct 30 155 days
32°F freeze Mar 26 · Apr 16 · May 5 Oct 6 · Oct 26 · Nov 14 192 days
28°F hard freeze Feb 21 · Mar 19 · Apr 12 Oct 23 · Nov 11 · Dec 5 236 days
NOAA NCEI U.S. Climate Normals 1991–2020, station USC00352997. How to read these probabilities.

Average high temperature by month

1991–2020 normals at Forest Grove

Average low temperature by month

Months with lows near or below freezing carry frost risk

Where these frost dates come from

The frost dates for Cornelius, OR come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Forest Grove (station USC00352997, elevation 180 ft), 2.5 mi from Cornelius. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.

Frost dates near Cornelius

CityDistanceLast spring frostFirst fall frost
Forest Grove, OR 3.1 mi Apr 16 Oct 26
Hillsboro, OR 5.6 mi Apr 16 Oct 23
Beaverton, OR 12 mi Apr 1 Nov 6
King City, OR 14 mi Apr 1 Nov 6
Tigard, OR 14 mi Apr 1 Nov 6
Sherwood, OR 15 mi Mar 21 Nov 22
Newberg, OR 16 mi Mar 21 Nov 22
Tualatin, OR 17 mi Apr 1 Nov 6
Lake Oswego, OR 19 mi Mar 18 Nov 18
Scappoose, OR 19 mi Apr 10 Nov 2

Frequently asked questions

When is the last frost in Cornelius?

On average, the last spring frost (32°F) in Cornelius is around April 16. In about 1 year in 10 it comes after May 5, and in 9 years in 10 it comes after March 26.

When is the first frost in Cornelius?

The first fall frost (32°F) usually arrives around October 26. There’s a 10% chance of a freeze by October 6 and a 90% chance by November 14.

Can it frost in Cornelius after the last frost date?

Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after May 4.

What growing zone is Cornelius?

Cornelius is in USDA Plant Hardiness Zone 8b (average annual extreme minimum temperature 15 to 20°F), based on the 2023 USDA map for ZIP code 97113. See growing zones in Oregon.

More: all Oregon frost dates · Oregon growing zones · frost vs. freeze