U.S. Frost Dates by Weather Station

NOAA station USC00101363 · Idaho

Frost Dates for Cabinet Gorge, ID

NOAA weather station Cabinet Gorge (USC00101363), Idaho · elevation 2173 ft (662 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 25only 1 spring in 10 still has a frost later
  • Typical last frostMay 950% chance of a frost after it
  • Typical first fall frostOctober 850% chance of a frost before it
  • Frost-free season153 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Cabinet Gorge, IDSpring: a frost after April 24 in 9 years out of 10, after May 9 in half of the years, after May 25 in 1 year out of 10. Fall: the first frost comes before September 25 in 1 year out of 10, before October 8 in half of the years, before October 26 in 9 years out of 10. Typical frost-free season: 153 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 9First frost ~Oct 8Frost season at Cabinet Gorge, IDSpring: a frost after April 24 in 9 years out of 10, after May 9 in half of the years, after May 25 in 1 year out of 10. Fall: the first frost comes before September 25 in 1 year out of 10, before October 8 in half of the years, before October 26 in 9 years out of 10. Typical frost-free season: 153 days.JFMAMJJASONDLast frost ~May 9First frost ~Oct 8
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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 25September 25
50% (typical)May 9October 8
90% (likely)April 24October 26
Frost-free season (32°F, 50% chance)
153 days
Hard frost (28°F), last in spring, 50% chance after
April 22
Hard frost (28°F), first in fall, 50% chance before
October 25

The last 15 years (2006–2020 normals)

Typical last frost May 5 (4 days earlier than the 30-year normal), typical first fall frost October 9 (1 day later). Frost-free season 157 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 Cabinet Gorge: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 25, 20% May 19, 30% May 15, 40% May 12, 50% May 9, 60% May 5, 70% May 2, 80% April 29, 90% April 24. Observed last spring frost in recent years: 2021 May 22, 2022 May 22, 2023 May 2, 2024 May 2, 2025 May 6, 2026 April 30.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 25May 9Apr 242021: May 222022: May 222023: May 22024: May 22025: May 62026: April 30Fall at Cabinet Gorge: chance of a frost before this dateFall, chance of a frost before the date: 10% September 25, 20% September 29, 30% October 2, 40% October 5, 50% October 8, 60% October 12, 70% October 16, 80% October 19, 90% October 26. Observed first fall frost in recent years: 2021 October 7, 2022 November 3, 2023 October 25, 2024 September 30, 2025 October 6.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 25Oct 8Oct 262021: October 72022: November 32023: October 252024: September 302025: October 6
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 22October 7
2022May 22November 3
2023May 2October 25
2024May 2September 30
2025May 6October 6
2026April 30season not over yet

What these dates mean

May 25 is the cautious spring date for light frost (32 °F) in Cabinet Gorge, and it gives a gardener the confidence to set out tender crops without exceeding a 10 % chance of a later frost. The earlier May 9 date marks the point at which there is a 50 % chance of a frost later than this date, while the April 24 gamble carries a 90 % chance of a later frost.

The 50 % dates, May 9 in spring and October 8 in fall, represent the median odds for light frost, meaning a 50 % chance of a frost later than May 9 and a 50 % chance of a frost earlier than October 8. The hard-frost (28 °F) median dates are April 22 and October 25; a hard frost can damage plants more severely than a light frost, so these dates are critical reference points.

September 25 is the cautious fall date for light frost, limiting the risk to 10 % for finishing the harvest of 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 25" 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 25" 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 Cabinet Gorge, IDNumbered nearest stations: 1 — Kellogg, ID — 38 mi; 2 — Priest River, ID — 40 mi; 3 — Libby Dam (Base), MT — 41 mi; 4 — Bonners Ferry, ID — 43 mi; 5 — near Thompson Falls, MT — 47 mi.MTIDWA25 mi · 40 km1. Kellogg, ID — 38 mi12. Priest River, ID — 40 mi23. Libby Dam (Base), MT — 41 mi34. Bonners Ferry, ID — 43 mi45. near Thompson Falls, MT — 47 mi5
  1. Kellogg, ID 38 mi (62 km)
  2. Priest River, ID 40 mi (65 km)
  3. Libby Dam (Base), MT 41 mi (65 km)
  4. Bonners Ferry, ID 43 mi (70 km)
  5. near Thompson Falls, MT 47 mi (76 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: 48.0864, -116.0572.