U.S. Frost Dates by Weather Station

NOAA station USW00024217 · Washington

Frost Dates for Bellingham (Airport), WA

NOAA weather station Bellingham International Airport (USW00024217), Washington · elevation 149 ft (45 m) · hardiness zone 8b*

  • Lower-risk planting dateafter April 18only 1 spring in 10 still has a frost later
  • Typical last frostMarch 3150% chance of a frost after it
  • Typical first fall frostOctober 3050% chance of a frost before it
  • Frost-free season211 daystypical year, 32°F
  • Hardiness zone8bcalculated*

The year at a glance

Frost season at Bellingham (Airport), WASpring: a frost after March 10 in 9 years out of 10, after March 31 in half of the years, after April 18 in 1 year out of 10. Fall: the first frost comes before October 12 in 1 year out of 10, before October 30 in half of the years, before November 17 in 9 years out of 10. Typical frost-free season: 211 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Mar 31First frost ~Oct 30Frost season at Bellingham (Airport), WASpring: a frost after March 10 in 9 years out of 10, after March 31 in half of the years, after April 18 in 1 year out of 10. Fall: the first frost comes before October 12 in 1 year out of 10, before October 30 in half of the years, before November 17 in 9 years out of 10. Typical frost-free season: 211 days.JFMAMJJASONDLast frost ~Mar 31First frost ~Oct 30
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)April 18October 12
50% (typical)March 31October 30
90% (likely)March 10November 17
Frost-free season (32°F, 50% chance)
211 days
Hard frost (28°F), last in spring, 50% chance after
March 4
Hard frost (28°F), first in fall, 50% chance before
November 16

The last 15 years (2006–2020 normals)

Typical last frost March 31 (same as the 30-year normal), typical first fall frost October 26 (4 days earlier). Frost-free season 210 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 Bellingham (Airport): chance of a frost after this dateSpring, chance of a frost after the date: 10% April 18, 20% April 12, 30% April 6, 40% April 2, 50% March 31, 60% March 26, 70% March 21, 80% March 17, 90% March 10. Observed last spring frost in recent years: 2021 April 12, 2022 April 20, 2023 April 14, 2024 April 19, 2025 April 13, 2026 April 9.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1May 1Apr 18Mar 31Mar 102021: April 122022: April 202023: April 142024: April 192025: April 132026: April 9Fall at Bellingham (Airport): chance of a frost before this dateFall, chance of a frost before the date: 10% October 12, 20% October 18, 30% October 23, 40% October 26, 50% October 30, 60% November 2, 70% November 5, 80% November 10, 90% November 17. Observed first fall frost in recent years: 2021 November 1, 2022 November 1, 2023 October 26, 2024 November 28, 2025 October 15.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Dec 1Oct 12Oct 30Nov 172021: November 12022: November 12023: October 262024: November 282025: 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 12November 1
2022April 20November 1
2023April 14October 26
2024April 19November 28
2025April 13October 15
2026April 9season not over yet

What these dates mean

October 12 is the cautious fall date for finishing the harvest of tender crops in Bellingham (Airport), because there is only a 10% chance that a light frost has arrived earlier; for spring planting, the cautious date is April 18, when a light frost later than that date occurs only 10% of the time, and planting before March 10 carries a 90% chance of frost and is a gamble. The 50% dates—March 31 in spring and October 30 in fall—mark the median point at which a light frost is equally likely to have occurred or not; they are reference points rather than frost dates. A hard frost at 28 °F, seen on the median dates of March 4 and November 16, can cause far more damage than a light frost at 32 °F, so it is 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 April 18" 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 12" 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 Bellingham (Airport), WANumbered nearest stations: 1 — near Bellingham, WA — 5 mi; 2 — Clearbrook, WA — 15 mi; 3 — Upper Baker Dam, WA — 40 mi; 4 — Concrete PPL Fish Station, WA — 40 mi; 5 — Coupeville, WA — 41 mi.WA25 mi · 40 km1. near Bellingham, WA — 5 mi12. Clearbrook, WA — 15 mi23. Upper Baker Dam, WA — 40 mi34. Concrete PPL Fish Station, WA — 40 mi45. Coupeville, WA — 41 mi5
  1. near Bellingham, WA 5 mi (9 km)
  2. Clearbrook, WA 15 mi (25 km)
  3. Upper Baker Dam, WA 40 mi (64 km)
  4. Concrete PPL Fish Station, WA 40 mi (65 km)
  5. Coupeville, WA 41 mi (66 km)

Sources

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

Station coordinates: 48.7939, -122.5372.