U.S. Frost Dates by Weather Station

NOAA station USC00451350 · Washington

Frost Dates for Chelan, WA

NOAA weather station Chelan (USC00451350), Washington · elevation 1194 ft (364 m) · hardiness zone 7b*

  • Lower-risk planting dateafter April 30only 1 spring in 10 still has a frost later
  • Typical last frostApril 1750% chance of a frost after it
  • Typical first fall frostOctober 2250% chance of a frost before it
  • Frost-free season187 daystypical year, 32°F
  • Hardiness zone7bcalculated*

The year at a glance

Frost season at Chelan, WASpring: a frost after April 3 in 9 years out of 10, after April 17 in half of the years, after April 30 in 1 year out of 10. Fall: the first frost comes before October 9 in 1 year out of 10, before October 22 in half of the years, before November 5 in 9 years out of 10. Typical frost-free season: 187 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 17First frost ~Oct 22Frost season at Chelan, WASpring: a frost after April 3 in 9 years out of 10, after April 17 in half of the years, after April 30 in 1 year out of 10. Fall: the first frost comes before October 9 in 1 year out of 10, before October 22 in half of the years, before November 5 in 9 years out of 10. Typical frost-free season: 187 days.JFMAMJJASONDLast frost ~Apr 17First frost ~Oct 22
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.Today

Frost dates (32°F)

Probability of frost, based on 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)April 30October 9
50% (typical)April 17October 22
90% (likely)April 3November 5
Frost-free season (32°F, 50% chance)
187 days
Hard frost (28°F), last in spring, 50% chance after
March 29
Hard frost (28°F), first in fall, 50% chance before
November 4

The last 15 years (2006–2020 normals)

Typical last frost April 20 (3 days later than the 30-year normal), typical first fall frost October 21 (1 day earlier). Frost-free season 184 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 Chelan: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 30, 20% April 27, 30% April 24, 40% April 21, 50% April 17, 60% April 14, 70% April 12, 80% April 8, 90% April 3. Observed last spring frost in recent years: 2021 April 14, 2022 April 28, 2023 April 20, 2025 April 13, 2026 April 26.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 30Apr 17Apr 32021: April 142022: April 282023: April 202025: April 132026: April 26Fall at Chelan: chance of a frost before this dateFall, chance of a frost before the date: 10% October 9, 20% October 13, 30% October 17, 40% October 20, 50% October 22, 60% October 25, 70% October 28, 80% October 31, 90% November 5. Observed first fall frost in recent years: 2021 October 8, 2022 October 23, 2023 October 23, 2024 October 23, 2025 October 15.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 9Oct 22Nov 52021: October 82022: October 232023: October 232024: October 232025: October 15
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 14October 8
2022April 28October 23
2023April 20October 23
2024incomplete recordOctober 23
2025April 13October 15
2026April 26season not over yet

What these dates mean

April 30 is the cautious spring date for Chelan; it carries a 10 % chance of a light frost later, so gardeners can plan to set out tender crops with only a low risk of frost damage.

The median, or 50 % date, for light frost in spring is April 17 and in fall is October 22; at those points the chance of a frost is even. The hard-frost 50 % dates are March 29 in spring and November 4 in fall, and a hard frost matters more because the colder 28 °F temperature can injure plants that survive a 32 °F light frost. October 9 is the cautious fall date, with a 10 % chance of a frost earlier, useful for timing the final 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 April 30" 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 October 9" 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 Chelan, WANumbered nearest stations: 1 — near Entiat, WA — 18 mi; 2 — near Bridgeport, WA — 20 mi; 3 — Plain, WA — 30 mi; 4 — Wenatchee, WA — 32 mi; 5 — Wenatchee (Pangborn Airport), WA — 32 mi.25 mi · 40 km1. near Entiat, WA — 18 mi12. near Bridgeport, WA — 20 mi23. Plain, WA — 30 mi34. Wenatchee, WA — 32 mi45. Wenatchee (Pangborn Airport), WA — 32 mi5
  1. near Entiat, WA 18 mi (28 km)
  2. near Bridgeport, WA 20 mi (32 km)
  3. Plain, WA 30 mi (48 km)
  4. Wenatchee, WA 32 mi (51 km)
  5. Wenatchee (Pangborn Airport), WA 32 mi (51 km)

Sources

* Hardiness zone 7b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 47.8344, -120.0006.