U.S. Frost Dates by Weather Station

NOAA station USW00024227 · Washington

Frost Dates for Olympia, WA

NOAA weather station Olympia Airport (USW00024227), Washington · elevation 188 ft (57 m) · hardiness zone 8a*

  • Lower-risk planting dateafter May 15only 1 spring in 10 still has a frost later
  • Typical last frostApril 2950% chance of a frost after it
  • Typical first fall frostOctober 1450% chance of a frost before it
  • Frost-free season169 daystypical year, 32°F
  • Hardiness zone8acalculated*

The year at a glance

Frost season at Olympia, WASpring: a frost after April 11 in 9 years out of 10, after April 29 in half of the years, after May 15 in 1 year out of 10. Fall: the first frost comes before September 28 in 1 year out of 10, before October 14 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 169 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 29First frost ~Oct 14Frost season at Olympia, WASpring: a frost after April 11 in 9 years out of 10, after April 29 in half of the years, after May 15 in 1 year out of 10. Fall: the first frost comes before September 28 in 1 year out of 10, before October 14 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 169 days.JFMAMJJASONDLast frost ~Apr 29First frost ~Oct 14
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 15September 28
50% (typical)April 29October 14
90% (likely)April 11November 1
Frost-free season (32°F, 50% chance)
169 days
Hard frost (28°F), last in spring, 50% chance after
April 5
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 30 (1 day later than the 30-year normal), typical first fall frost October 13 (1 day earlier). Frost-free season 167 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 Olympia: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 15, 20% May 9, 30% May 5, 40% May 2, 50% April 29, 60% April 27, 70% April 23, 80% April 18, 90% April 11. Observed last spring frost in recent years: 2021 April 15, 2022 May 11, 2023 April 20, 2024 May 8, 2025 May 5, 2026 May 17.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 15Apr 29Apr 112021: April 152022: May 112023: April 202024: May 82025: May 52026: May 17Fall at Olympia: chance of a frost before this dateFall, chance of a frost before the date: 10% September 28, 20% October 3, 30% October 6, 40% October 10, 50% October 14, 60% October 18, 70% October 21, 80% October 26, 90% November 1. Observed first fall frost in recent years: 2021 October 11, 2022 October 23, 2023 October 26, 2024 October 23, 2025 October 13.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 28Oct 14Nov 12021: October 112022: October 232023: October 262024: October 232025: 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
2021April 15October 11
2022May 11October 23
2023April 20October 26
2024May 8October 23
2025May 5October 13
2026May 17season not over yet

What these dates mean

There are 169 days between the 32°F 50% dates in Olympia, from April 29 to October 14, and they define the interval where a light frost is as likely as not.

The 50% dates are reference points; the chance of a frost later than April 29 in spring or earlier than October 14 in fall is 50%, but they are not frost dates themselves. Gardeners who prefer low risk would wait until the cautious spring date of May 15, which carries only a 10% chance of a frost later, and would aim to finish tender crops by the cautious fall date of September 28, which carries only a 10% chance of a frost earlier.

A hard frost at 28°F can damage plant tissue that usually survives a light frost at 32°F, making it a more critical threshold for gardeners.

How to read the probabilities

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

  • Spring: "10% after May 15" 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 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 Olympia, WANumbered nearest stations: 1 — Elma, WA — 24 mi; 2 — near Tacoma, WA — 30 mi; 3 — Cushman Powerhouse #2, WA — 30 mi; 4 — Seattle (Seattle-Tacoma Airport), WA — 43 mi; 5 — Kent, WA — 44 mi.WA25 mi · 40 km1. Elma, WA — 24 mi12. near Tacoma, WA — 30 mi23. Cushman Powerhouse #2, WA — 30 mi34. Seattle (Seattle-Tacoma Airport), WA — 43 mi45. Kent, WA — 44 mi5
  1. Elma, WA 24 mi (38 km)
  2. near Tacoma, WA 30 mi (48 km)
  3. Cushman Powerhouse #2, WA 30 mi (48 km)
  4. Seattle (Seattle-Tacoma Airport), WA 43 mi (69 km)
  5. Kent, WA 44 mi (70 km)

Sources

* Hardiness zone 8a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 46.9733, -122.9033.