U.S. Frost Dates by Weather Station

NOAA station USW00024157 · Washington

Frost Dates for Spokane, WA

NOAA weather station Spokane International Airport (USW00024157), Washington · elevation 2353 ft (717 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 10only 1 spring in 10 still has a frost later
  • Typical last frostApril 2650% chance of a frost after it
  • Typical first fall frostOctober 1250% chance of a frost before it
  • Frost-free season168 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Spokane, WASpring: a frost after April 9 in 9 years out of 10, after April 26 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before September 29 in 1 year out of 10, before October 12 in half of the years, before October 28 in 9 years out of 10. Typical frost-free season: 168 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 26First frost ~Oct 12Frost season at Spokane, WASpring: a frost after April 9 in 9 years out of 10, after April 26 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before September 29 in 1 year out of 10, before October 12 in half of the years, before October 28 in 9 years out of 10. Typical frost-free season: 168 days.JFMAMJJASONDLast frost ~Apr 26First frost ~Oct 12
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 26 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 10September 29
50% (typical)April 26October 12
90% (likely)April 9October 28
Frost-free season (32°F, 50% chance)
168 days
Hard frost (28°F), last in spring, 50% chance after
April 6
Hard frost (28°F), first in fall, 50% chance before
October 23

The last 15 years (2006–2020 normals)

Typical last frost April 26 (same as the 30-year normal), typical first fall frost October 14 (2 days later). Frost-free season 171 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 Spokane: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 10, 20% May 5, 30% May 2, 40% April 29, 50% April 26, 60% April 23, 70% April 20, 80% April 15, 90% April 9. Observed last spring frost in recent years: 2021 April 12, 2022 April 22, 2023 April 20, 2024 April 30, 2025 April 13, 2026 April 24.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 10Apr 26Apr 92021: April 122022: April 222023: April 202024: April 302025: April 132026: April 24Fall at Spokane: chance of a frost before this dateFall, chance of a frost before the date: 10% September 29, 20% October 3, 30% October 6, 40% October 9, 50% October 12, 60% October 15, 70% October 18, 80% October 22, 90% October 28. Observed first fall frost in recent years: 2021 October 11, 2022 October 23, 2023 October 25, 2024 October 18, 2025 October 18.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 29Oct 12Oct 282021: October 112022: October 232023: October 252024: October 182025: October 18
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 12October 11
2022April 22October 23
2023April 20October 25
2024April 30October 18
2025April 13October 18
2026April 24season not over yet

What these dates mean

Setting out tender crops on April 9 in Spokane carries a 90 % chance of a light frost later, making it a gamble for any gardener. The cautious approach waits until May 10, when only a 10 % chance of a frost remains, for planting those sensitive varieties.

The 50 % dates mark the point where the odds of a light frost are even. In spring the median date is April 26, meaning a 50 % chance of frost later; in fall the median date is October 12, meaning a 50 % chance of frost earlier. A careful season finishes harvesting tender crops by September 29, the fall cautious date with only a 10 % chance that a frost has arrived. The hard-frost 50 % dates, April 6 and October 23, are important because a 28 °F frost can damage or kill plants more severely than a 32 °F light frost.

How to read the probabilities

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

  • Spring: "10% after May 10" 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 29" 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 Spokane, WANumbered nearest stations: 1 — Davenport, WA — 30 mi; 2 — St. John, WA — 37 mi; 3 — Chewelah, WA — 46 mi; 4 — Saint Maries, ID — 49 mi; 5 — Ritzville, WA — 53 mi.IDMT25 mi · 40 km1. Davenport, WA — 30 mi12. St. John, WA — 37 mi23. Chewelah, WA — 46 mi34. Saint Maries, ID — 49 mi45. Ritzville, WA — 53 mi5
  1. Davenport, WA 30 mi (48 km)
  2. St. John, WA 37 mi (59 km)
  3. Chewelah, WA 46 mi (74 km)
  4. Saint Maries, ID 49 mi (79 km)
  5. Ritzville, WA 53 mi (85 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: 47.6217, -117.5281.