U.S. Frost Dates by Weather Station

NOAA station USC00356532 · Oregon

Frost Dates near Warm Springs, OR

NOAA weather station Pelton Dam (USC00356532), Oregon · elevation 1410 ft (430 m) · hardiness zone 7b*

Warm Springs is the nearest town to the station (2.6 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 550% chance of a frost after it
  • Typical first fall frostOctober 750% chance of a frost before it
  • Frost-free season154 daystypical year, 32°F
  • Hardiness zone7bcalculated*

The year at a glance

Frost season near Warm Springs, ORSpring: a frost after April 21 in 9 years out of 10, after May 5 in half of the years, after May 29 in 1 year out of 10. Fall: the first frost comes before September 24 in 1 year out of 10, before October 7 in half of the years, before October 22 in 9 years out of 10. Typical frost-free season: 154 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 5First frost ~Oct 7Frost season near Warm Springs, ORSpring: a frost after April 21 in 9 years out of 10, after May 5 in half of the years, after May 29 in 1 year out of 10. Fall: the first frost comes before September 24 in 1 year out of 10, before October 7 in half of the years, before October 22 in 9 years out of 10. Typical frost-free season: 154 days.JFMAMJJASONDLast frost ~May 5First frost ~Oct 7
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 24
50% (typical)May 5October 7
90% (likely)April 21October 22
Frost-free season (32°F, 50% chance)
154 days
Hard frost (28°F), last in spring, 50% chance after
April 20
Hard frost (28°F), first in fall, 50% chance before
October 20

The last 15 years (2006–2020 normals)

Typical last frost April 30 (5 days earlier than the 30-year normal), typical first fall frost October 11 (4 days later). Frost-free season 163 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 Warm Springs: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 29, 20% May 18, 30% May 13, 40% May 9, 50% May 5, 60% May 2, 70% April 30, 80% April 27, 90% April 21. Observed last spring frost in recent years: 2021 April 27, 2022 May 21, 2023 April 20, 2024 May 7, 2025 April 24.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 29May 5Apr 212021: April 272022: May 212023: April 202024: May 72025: April 24Fall near Warm Springs: chance of a frost before this dateFall, chance of a frost before the date: 10% September 24, 20% October 1, 30% October 3, 40% October 5, 50% October 7, 60% October 10, 70% October 13, 80% October 17, 90% October 22. Observed first fall frost in recent years: 2021 October 7, 2022 October 23, 2024 October 24, 2025 October 16.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 24Oct 7Oct 222021: October 72022: October 232024: October 242025: October 16
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 27October 7
2022May 21October 23
2023April 20incomplete record
2024May 7October 24
2025April 24October 16
2026incomplete recordseason not over yet

What these dates mean

The cautious fall date for finishing the harvest in the Warm Springs area is September 24, when there is only a 10 % chance that a light frost has arrived.

For light frost, the 50 % date is May 5 in spring and October 7 in fall; each marks the point where a light frost is equally likely to occur later (spring) or earlier (fall). For hard frost, the 50 % dates are April 20 and October 20, indicating an even chance of a 28 °F event.

A cautious planting plan uses May 29 as the spring date for tender crops and September 24 as the fall date to finish harvesting them. Because a hard frost at 28 °F can damage plant tissue that survives a light frost at 32 °F, it is a greater risk for sensitive plants.

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 24" 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 Warm Springs, ORNumbered nearest stations: 1 — near Redmond, OR — 33 mi; 2 — Marion Forks Fish Hatchery, OR — 35 mi; 3 — Government Camp, OR — 46 mi; 4 — Three Lynx, OR — 48 mi; 5 — Moro, OR — 58 mi.WA25 mi · 40 km1. near Redmond, OR — 33 mi12. Marion Forks Fish Hatchery, OR — 35 mi23. Government Camp, OR — 46 mi34. Three Lynx, OR — 48 mi45. Moro, OR — 58 mi5
  1. near Redmond, OR 33 mi (53 km)
  2. Marion Forks Fish Hatchery, OR 35 mi (57 km)
  3. Government Camp, OR 46 mi (75 km)
  4. Three Lynx, OR 48 mi (78 km)
  5. Moro, OR 58 mi (94 km)

Sources

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

Station coordinates: 44.7275, -121.2506.