U.S. Frost Dates by Weather Station

NOAA station USW00024155 · Oregon

Frost Dates for Pendleton, OR

NOAA weather station Pendleton (USW00024155), Oregon · elevation 1515 ft (462 m) · hardiness zone 7a*

  • Lower-risk planting dateafter May 10only 1 spring in 10 still has a frost later
  • Typical last frostApril 2650% chance of a frost after it
  • Typical first fall frostOctober 1650% chance of a frost before it
  • Frost-free season174 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Pendleton, ORSpring: a frost after April 7 in 9 years out of 10, after April 26 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 16 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 174 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 26First frost ~Oct 16Frost season at Pendleton, ORSpring: a frost after April 7 in 9 years out of 10, after April 26 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 16 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 174 days.JFMAMJJASONDLast frost ~Apr 26First frost ~Oct 16
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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 10October 1
50% (typical)April 26October 16
90% (likely)April 7November 1
Frost-free season (32°F, 50% chance)
174 days
Hard frost (28°F), last in spring, 50% chance after
April 1
Hard frost (28°F), first in fall, 50% chance before
October 28

The last 15 years (2006–2020 normals)

Typical last frost April 25 (1 day earlier than the 30-year normal), typical first fall frost October 14 (2 days earlier). Frost-free season 174 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 Pendleton: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 10, 20% May 5, 30% May 2, 40% April 28, 50% April 26, 60% April 22, 70% April 18, 80% April 13, 90% April 7. Observed last spring frost in recent years: 2021 April 20, 2022 April 20, 2023 April 20, 2024 April 22, 2025 April 23, 2026 April 26.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 10Apr 26Apr 72021: April 202022: April 202023: April 202024: April 222025: April 232026: April 26Fall at Pendleton: chance of a frost before this dateFall, chance of a frost before the date: 10% October 1, 20% October 6, 30% October 9, 40% October 13, 50% October 16, 60% October 18, 70% October 22, 80% October 26, 90% November 1. Observed first fall frost in recent years: 2021 October 11, 2022 November 3, 2023 October 27, 2024 October 25, 2025 October 15.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 1Oct 16Nov 12021: October 112022: November 32023: October 272024: October 252025: October 15
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 20October 11
2022April 20November 3
2023April 20October 27
2024April 22October 25
2025April 23October 15
2026April 26season not over yet

What these dates mean

The 174 days between the 32°F 50% dates in Pendleton – April 26 and October 16 – frame a period in which a light frost is no more likely than not. At the spring 50% date there is a 50% chance a frost will occur later, and at the fall 50% date there is a 50% chance a frost will have occurred earlier. Gardeners can use these markers to gauge the overall risk window across the 29-year record.

May 10 carries a 10% chance of a frost later than that date and is the cautious date for setting out tender crops in spring, while October 1 carries a 10% chance of a frost earlier than that date and is the cautious date for finishing harvest of tender crops in fall. The hard-frost 50% dates are April 1 and October 28; a hard frost at 28 °F can damage plants more severely than a light frost at 32 °F.

How to read the probabilities

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

  • Spring: "10% after May 10" 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 1" 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 Pendleton, ORNumbered nearest stations: 1 — Pilot Rock, OR — 15 mi; 2 — Milton Freewater, OR — 28 mi; 3 — Whitman Mission, WA — 31 mi; 4 — Kennewick, WA — 38 mi; 5 — near Burbank, WA — 38 mi.25 mi · 40 km1. Pilot Rock, OR — 15 mi12. Milton Freewater, OR — 28 mi23. Whitman Mission, WA — 31 mi34. Kennewick, WA — 38 mi45. near Burbank, WA — 38 mi5
  1. Pilot Rock, OR 15 mi (24 km)
  2. Milton Freewater, OR 28 mi (44 km)
  3. Whitman Mission, WA 31 mi (50 km)
  4. Kennewick, WA 38 mi (61 km)
  5. near Burbank, WA 38 mi (62 km)

Sources

* Hardiness zone 7a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 45.6906, -118.8528.