U.S. Frost Dates by Weather Station

NOAA station USC00456974 · Washington

Frost Dates for Republic, WA

NOAA weather station Republic (USC00456974), Washington · elevation 2555 ft (779 m) · hardiness zone 6a*

  • Lower-risk planting dateafter June 17only 1 spring in 10 still has a frost later
  • Typical last frostMay 3050% chance of a frost after it
  • Typical first fall frostSeptember 1050% chance of a frost before it
  • Frost-free season102 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Republic, WASpring: a frost after May 11 in 9 years out of 10, after May 30 in half of the years, after June 17 in 1 year out of 10. Fall: the first frost comes before August 28 in 1 year out of 10, before September 10 in half of the years, before September 25 in 9 years out of 10. Typical frost-free season: 102 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 30First frost ~Sep 10Frost season at Republic, WASpring: a frost after May 11 in 9 years out of 10, after May 30 in half of the years, after June 17 in 1 year out of 10. Fall: the first frost comes before August 28 in 1 year out of 10, before September 10 in half of the years, before September 25 in 9 years out of 10. Typical frost-free season: 102 days.JFMAMJJASONDLast frost ~May 30First 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 27 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)June 17August 28
50% (typical)May 30September 10
90% (likely)May 11September 25
Frost-free season (32°F, 50% chance)
102 days
Hard frost (28°F), last in spring, 50% chance after
May 12
Hard frost (28°F), first in fall, 50% chance before
September 24

The last 15 years (2006–2020 normals)

Typical last frost May 29 (1 day earlier than the 30-year normal), typical first fall frost September 10. Frost-free season 106 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 Republic: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 17, 20% June 11, 30% June 5, 40% June 1, 50% May 30, 60% May 27, 70% May 23, 80% May 17, 90% May 11. Observed last spring frost in recent years: 2021 June 7, 2022 May 30, 2023 April 28.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jul 1Jun 17May 30May 112021: June 72022: May 302023: April 28Fall at Republic: chance of a frost before this dateFall, chance of a frost before the date: 10% August 28, 20% September 2, 30% September 5, 40% September 7, 50% September 10, 60% September 13, 70% September 16, 80% September 20, 90% September 25. Observed first fall frost in recent years: 2021 September 16, 2022 October 13.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Aug 28Sep 10Sep 252021: September 162022: October 13
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
2021June 7September 16
2022May 30October 13
2023April 28no data
2024no datano data
2025no datano data
2026no dataseason not over yet

What these dates mean

June 17 is the cautious spring date, with only a 10% chance of a light frost later, and it is the date a gardener can safely plan to set out tender crops.

May 30 is the 50% date, indicating a 50% chance of a frost later than this date, while September 10 is the 50% date for fall, giving a 50% chance of a frost earlier than this date. The 50% dates for hard frost are May 12 and September 24, each representing an even-odds point for a frost of 28 °F. For a cautious fall schedule the 10% chance date is August 28, when the likelihood of a light frost earlier than that day is low enough to finish harvesting tender crops. A hard frost at 28 °F matters more than a light frost at 32 °F because it can damage plant tissue that survives a milder freeze.

How to read the probabilities

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

  • Spring: "10% after June 17" 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 28" 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 Republic, WANumbered nearest stations: 1 — Northport, WA — 45 mi; 2 — Coulee Dam, WA — 49 mi; 3 — Chewelah, WA — 52 mi; 4 — Wilbur, WA — 61 mi; 5 — near Bridgeport, WA — 61 mi.WAID25 mi · 40 km1. Northport, WA — 45 mi12. Coulee Dam, WA — 49 mi23. Chewelah, WA — 52 mi34. Wilbur, WA — 61 mi45. near Bridgeport, WA — 61 mi5
  1. Northport, WA 45 mi (72 km)
  2. Coulee Dam, WA 49 mi (79 km)
  3. Chewelah, WA 52 mi (84 km)
  4. Wilbur, WA 61 mi (98 km)
  5. near Bridgeport, WA 61 mi (99 km)

Sources

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

Station coordinates: 48.6461, -118.7369.