U.S. Frost Dates by Weather Station

NOAA station USC00352374 · Oregon

Frost Dates for Dorena, OR

NOAA weather station Dorena (USC00352374), Oregon · elevation 820 ft (250 m) · hardiness zone 8b*

  • Lower-risk planting dateafter May 11only 1 spring in 10 still has a frost later
  • Typical last frostApril 1650% chance of a frost after it
  • Typical first fall frostOctober 2850% chance of a frost before it
  • Frost-free season194 daystypical year, 32°F
  • Hardiness zone8bcalculated*

The year at a glance

Frost season at Dorena, ORSpring: a frost after March 24 in 9 years out of 10, after April 16 in half of the years, after May 11 in 1 year out of 10. Fall: the first frost comes before October 4 in 1 year out of 10, before October 28 in half of the years, before November 23 in 9 years out of 10. Typical frost-free season: 194 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 16First frost ~Oct 28Frost season at Dorena, ORSpring: a frost after March 24 in 9 years out of 10, after April 16 in half of the years, after May 11 in 1 year out of 10. Fall: the first frost comes before October 4 in 1 year out of 10, before October 28 in half of the years, before November 23 in 9 years out of 10. Typical frost-free season: 194 days.JFMAMJJASONDLast frost ~Apr 16First frost ~Oct 28
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 27 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 11October 4
50% (typical)April 16October 28
90% (likely)March 24November 23
Frost-free season (32°F, 50% chance)
194 days
Hard frost (28°F), last in spring, 50% chance after
March 12
Hard frost (28°F), first in fall, 50% chance before
November 21

The last 15 years (2006–2020 normals)

Typical last frost April 24 (8 days later than the 30-year normal), typical first fall frost October 28. Frost-free season 190 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 at Dorena: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 11, 20% May 2, 30% April 27, 40% April 22, 50% April 16, 60% April 10, 70% April 4, 80% March 31, 90% March 24. Observed last spring frost in recent years: 2021 April 14, 2022 April 16, 2023 April 17, 2024 April 22, 2025 April 14, 2026 April 17.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 11Apr 16Mar 242021: April 142022: April 162023: April 172024: April 222025: April 142026: April 17Fall at Dorena: chance of a frost before this dateFall, chance of a frost before the date: 10% October 4, 20% October 13, 30% October 19, 40% October 23, 50% October 28, 60% November 1, 70% November 5, 80% November 12, 90% November 23. Observed first fall frost in recent years: 2021 September 14, 2022 November 3, 2023 October 26, 2024 October 24.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Dec 1Oct 4Oct 28Nov 232021: September 142022: November 32023: October 262024: October 24
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
2021April 14September 14
2022April 16November 3
2023April 17October 26
2024April 22October 24
2025April 14incomplete record
2026April 17season not over yet

What these dates mean

The 194 days between the 32°F 50% dates in Dorena, April 16 and October 28, define the window when light frosts are equally probable on either side. Within that span gardeners can plan most of their growing activities, while outside it the risk of a light frost rises sharply.

The 50% dates themselves are points where a 32°F frost has a 50 % chance of having occurred. For a cautious spring planting schedule the date with only a 10 % chance of a later frost is May 11, while in fall the cautious date to finish tender crops is October 4, each carrying a low risk of a light frost.

Hard frosts at 28°F, marked by the 50% dates March 12 and November 21, can cause far greater damage to plants than the milder 32°F light frosts.

How to read the probabilities

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

  • Spring: "10% after May 11" 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 October 4" 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 Dorena, ORNumbered nearest stations: 1 — Cottage Grove, OR — 3 mi; 2 — near Lowell, OR — 14 mi; 3 — Drain, OR — 20 mi; 4 — Leaburg, OR — 26 mi; 5 — near Oakridge, OR — 26 mi.25 mi · 40 km1. Cottage Grove, OR — 3 mi12. near Lowell, OR — 14 mi23. Drain, OR — 20 mi34. Leaburg, OR — 26 mi45. near Oakridge, OR — 26 mi5
  1. Cottage Grove, OR 3 mi (5 km)
  2. near Lowell, OR 14 mi (22 km)
  3. Drain, OR 20 mi (32 km)
  4. Leaburg, OR 26 mi (42 km)
  5. near Oakridge, OR 26 mi (42 km)

Sources

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

Station coordinates: 43.7822, -122.9631.