U.S. Frost Dates by Weather Station

NOAA station USC00358884 · Oregon

Frost Dates near Vernonia, OR

NOAA weather station Vernonia #2 (USC00358884), Oregon · elevation 625 ft (191 m) · hardiness zone 8a*

Vernonia is the nearest town to the station (0.5 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter May 29only 1 spring in 10 still has a frost later
  • Typical last frostMay 850% chance of a frost after it
  • Typical first fall frostOctober 150% chance of a frost before it
  • Frost-free season144 daystypical year, 32°F
  • Hardiness zone8acalculated*

The year at a glance

Frost season near Vernonia, ORSpring: a frost after April 18 in 9 years out of 10, after May 8 in half of the years, after May 29 in 1 year out of 10. Fall: the first frost comes before September 11 in 1 year out of 10, before October 1 in half of the years, before October 28 in 9 years out of 10. Typical frost-free season: 144 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 8First frost ~Oct 1Frost season near Vernonia, ORSpring: a frost after April 18 in 9 years out of 10, after May 8 in half of the years, after May 29 in 1 year out of 10. Fall: the first frost comes before September 11 in 1 year out of 10, before October 1 in half of the years, before October 28 in 9 years out of 10. Typical frost-free season: 144 days.JFMAMJJASONDLast frost ~May 8First frost ~Oct 1
frost likely chance fading 90% → 10% frost-free in a typical yearThe year at a glance. Blue: frost is likely; the gradient fades as the chance drops from 90% to 10%; green: the frost-free part of a typical year.

Frost dates (32°F)

Probability of frost, based on 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 29September 11
50% (typical)May 8October 1
90% (likely)April 18October 28
Frost-free season (32°F, 50% chance)
144 days
Hard frost (28°F), last in spring, 50% chance after
April 12
Hard frost (28°F), first in fall, 50% chance before
October 21

The last 15 years (2006–2020 normals)

Typical last frost May 5 (3 days earlier than the 30-year normal), typical first fall frost October 3 (2 days later). Frost-free season 149 days.

A shorter, more recent NOAA period. The 30-year normals above remain the main reference: 15 years carry more year-to-year noise.

Add these dates to your calendar Yearly reminders for the typical last frost, the lower-risk planting date and the typical first fall frost (.ics).

How the chance of frost changes with the date

Spring near Vernonia: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 29, 20% May 23, 30% May 17, 40% May 12, 50% May 8, 60% May 2, 70% April 30, 80% April 26, 90% April 18. Observed last spring frost in recent years: 2021 May 20, 2022 May 19, 2023 May 31, 2024 May 8, 2025 May 9, 2026 April 26.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 29May 8Apr 182021: May 202022: May 192023: May 312024: May 82025: May 92026: April 26Fall near Vernonia: chance of a frost before this dateFall, chance of a frost before the date: 10% September 11, 20% September 18, 30% September 24, 40% September 28, 50% October 1, 60% October 6, 70% October 10, 80% October 18, 90% October 28. Observed first fall frost in recent years: 2021 September 15, 2022 November 8, 2023 October 27, 2024 October 2, 2025 October 13.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Nov 1Sep 11Oct 1Oct 282021: September 152022: November 82023: October 272024: October 22025: October 13
Two charts, because spring and fall answer different questions: in spring, the chance that a frost still comes after a date; in fall, the chance that the first frost has already come before it. NOAA publishes these odds from 10% to 90%, so the lines stop there. ◆ marks the actual date in each recent year.

What actually happened in recent years

Observed dates of the last spring and first fall frost (32°F) at this station; ◆ marks them on the charts above
YearLast spring frostFirst fall frost
2021May 20September 15
2022May 19November 8
2023May 31October 27
2024May 8October 2
2025May 9October 13
2026April 26season not over yet

What these dates mean

May 29 is the cautious spring date for the Vernonia area, with only a 10 % chance of a light frost occurring later, so a gardener can plan to set out tender crops after that day with minimal risk.

The median light-frost dates are May 8 in spring and October 1 in fall, each representing an even-odds 50 % chance of a frost later or earlier, respectively. The median hard-frost dates are April 12 in spring and October 21 in fall, indicating where the probability of a 28 °F event is one-half. For a conservative schedule, the cautious fall date is September 11, when there is only a 10 % chance a light frost has arrived, while planting on April 18 or counting on crops through October 28 carries a 90 % risk.

A hard frost at 28 °F can damage plants that would survive a light frost at 32 °F, making those dates especially important for protecting tender crops.

How to read the probabilities

The dates are probabilities from 30 years of weather, not a forecast for this year.

  • Spring: "10% after May 29" means that in about one spring out of ten a frost still happens after that date. The 90% date is the earliest: a frost after it happens in most years.
  • Fall: "10% before September 11" means that in about one fall out of ten the first frost arrives before that date.
  • 50% is the typical date: half of the years are earlier, half are later.
  • A light frost (32°F) damages tender plants; a hard frost (28°F) also stops most hardy vegetables.

Nearby weather stations

Map of weather stations near Vernonia, ORNumbered nearest stations: 1 — Clatskanie, OR — 17 mi; 2 — Longview, WA — 24 mi; 3 — Forest Grove, OR — 24 mi; 4 — Vancouver, WA — 29 mi; 5 — Battle Ground, WA — 33 mi.ORWA25 mi · 40 km1. Clatskanie, OR — 17 mi12. Longview, WA — 24 mi23. Forest Grove, OR — 24 mi34. Vancouver, WA — 29 mi45. Battle Ground, WA — 33 mi5
  1. Clatskanie, OR 17 mi (27 km)
  2. Longview, WA 24 mi (38 km)
  3. Forest Grove, OR 24 mi (38 km)
  4. Vancouver, WA 29 mi (47 km)
  5. Battle Ground, WA 33 mi (52 km)

Sources

* Hardiness zone 8a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 45.8653, -123.1903.