U.S. Frost Dates by Weather Station

NOAA station USC00357310 · Oregon

Frost Dates for Rome, OR

NOAA weather station Rome 2 NW (USC00357310), Oregon · elevation 3405 ft (1038 m) · hardiness zone 6b*

  • Lower-risk planting dateafter July 3only 1 spring in 10 still has a frost later
  • Typical last frostJune 1150% chance of a frost after it
  • Typical first fall frostSeptember 1050% chance of a frost before it
  • Frost-free season88 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Rome, ORSpring: a frost after May 20 in 9 years out of 10, after June 11 in half of the years, after July 3 in 1 year out of 10. Fall: the first frost comes before August 27 in 1 year out of 10, before September 10 in half of the years, before September 24 in 9 years out of 10. Typical frost-free season: 88 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Jun 11First frost ~Sep 10Frost season at Rome, ORSpring: a frost after May 20 in 9 years out of 10, after June 11 in half of the years, after July 3 in 1 year out of 10. Fall: the first frost comes before August 27 in 1 year out of 10, before September 10 in half of the years, before September 24 in 9 years out of 10. Typical frost-free season: 88 days.JFMAMJJASONDLast frost ~Jun 11First frost ~Sep 10
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)July 3August 27
50% (typical)June 11September 10
90% (likely)May 20September 24
Frost-free season (32°F, 50% chance)
88 days
Hard frost (28°F), last in spring, 50% chance after
May 22
Hard frost (28°F), first in fall, 50% chance before
September 21

The last 15 years (2006–2020 normals)

Typical last frost June 2 (9 days earlier than the 30-year normal), typical first fall frost September 10. Frost-free season 97 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 Rome: chance of a frost after this dateSpring, chance of a frost after the date: 10% July 3, 20% June 25, 30% June 20, 40% June 15, 50% June 11, 60% June 7, 70% June 2, 80% May 29, 90% May 20. Observed last spring frost in recent years: 2021 May 22, 2023 June 21, 2024 June 20, 2025 May 21, 2026 June 11.Spring: last frostChance of a frost after this date10%50%90%Jun 1Jul 1Jul 3Jun 11May 202021: May 222023: June 212024: June 202025: May 212026: June 11Fall at Rome: chance of a frost before this dateFall, chance of a frost before the date: 10% August 27, 20% September 1, 30% September 4, 40% September 7, 50% September 10, 60% September 12, 70% September 15, 80% September 19, 90% September 24. Observed first fall frost in recent years: 2021 September 1, 2022 September 10, 2024 August 30, 2025 September 16.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Aug 27Sep 10Sep 242021: September 12022: September 102024: August 302025: September 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
2021May 22September 1
2022incomplete recordSeptember 10
2023June 21incomplete record
2024June 20August 30
2025May 21September 16
2026June 11season not over yet

What these dates mean

August 27 is the cautious fall date in Rome for finishing the harvest of tender crops, carrying only a 10% chance that a light frost has arrived earlier. The 50% fall date is September 10; there is a 50% chance of a frost earlier than this date, marking the median point of risk for light frosts.

Spring cautious planting uses July 3, when the chance of a light frost later than that date is just 10%. The 50% spring date is June 11, with a 50% chance of a frost later than this date. The 50% hard-frost dates are May 22 in spring and September 21 in fall. Hard frost at 28 °F can cause greater damage to seedlings than a light frost at 32 °F because it reaches lower temperatures.

How to read the probabilities

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

  • Spring: "10% after July 3" 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 August 27" 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 Rome, ORNumbered nearest stations: 1 — near Murphy, ID — 70 mi; 2 — Burns, OR — 83 mi; 3 — Boise (Air Terminal), ID — 86 mi; 4 — Orovada, NV — 90 mi; 5 — Emmett, ID — 91 mi.ORIDNVCA50 mi · 80 km1. near Murphy, ID — 70 mi12. Burns, OR — 83 mi23. Boise (Air Terminal), ID — 86 mi34. Orovada, NV — 90 mi45. Emmett, ID — 91 mi5
  1. near Murphy, ID 70 mi (112 km)
  2. Burns, OR 83 mi (133 km)
  3. Boise (Air Terminal), ID 86 mi (139 km)
  4. Orovada, NV 90 mi (144 km)
  5. Emmett, ID 91 mi (147 km)

Sources

* Hardiness zone 6b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 42.8592, -117.6569.