U.S. Frost Dates by Weather Station

NOAA station USC00450587 · Washington

Frost Dates near Bellingham, WA

NOAA weather station Bellingham 3 SSW (USC00450587), Washington · elevation 15 ft (5 m) · hardiness zone 8b*

Bellingham is the nearest town to the station (3.0 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter April 24only 1 spring in 10 still has a frost later
  • Typical last frostApril 150% chance of a frost after it
  • Typical first fall frostNovember 250% chance of a frost before it
  • Frost-free season216 daystypical year, 32°F
  • Hardiness zone8bcalculated*

The year at a glance

Frost season near Bellingham, WASpring: a frost after March 11 in 9 years out of 10, after April 1 in half of the years, after April 24 in 1 year out of 10. Fall: the first frost comes before October 15 in 1 year out of 10, before November 2 in half of the years, before November 23 in 9 years out of 10. Typical frost-free season: 216 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 1First frost ~Nov 2Frost season near Bellingham, WASpring: a frost after March 11 in 9 years out of 10, after April 1 in half of the years, after April 24 in 1 year out of 10. Fall: the first frost comes before October 15 in 1 year out of 10, before November 2 in half of the years, before November 23 in 9 years out of 10. Typical frost-free season: 216 days.JFMAMJJASONDLast frost ~Apr 1First frost ~Nov 2
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)April 24October 15
50% (typical)April 1November 2
90% (likely)March 11November 23
Frost-free season (32°F, 50% chance)
216 days
Hard frost (28°F), last in spring, 50% chance after
March 6
Hard frost (28°F), first in fall, 50% chance before
November 21

The last 15 years (2006–2020 normals)

Typical last frost April 1 (same as the 30-year normal), typical first fall frost October 31 (2 days earlier). Frost-free season 212 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 near Bellingham: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 24, 20% April 14, 30% April 8, 40% April 3, 50% April 1, 60% March 28, 70% March 22, 80% March 18, 90% March 11. Observed last spring frost in recent years: 2021 April 12, 2022 April 20.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1May 1Apr 24Apr 1Mar 112021: April 122022: April 20Fall near Bellingham: chance of a frost before this dateFall, chance of a frost before the date: 10% October 15, 20% October 22, 30% October 26, 40% October 30, 50% November 2, 60% November 7, 70% November 11, 80% November 16, 90% November 23. Observed first fall frost in recent years: 2021 October 30, 2022 November 3.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Dec 1Oct 15Nov 2Nov 232021: October 302022: November 3
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 30
2022April 20November 3
2023incomplete recordno data
2024no datano data
2025no datano data
2026no dataseason not over yet

What these dates mean

Setting out tender crops on March 11 in the Bellingham area is a gamble, because there is a 90% chance of a light frost later that day.

The 50% light-frost dates—April 1 in spring and November 2 in fall—mark the point at which a frost is equally likely to have occurred or not; similarly, the 50% hard-frost dates—March 6 and November 21—indicate an even chance of temperatures reaching 28 °F.

Gardeners who prefer a lower risk wait until the cautious spring date of April 24 and the cautious fall date of October 15 to plant or finish harvesting tender crops. A hard frost matters more than a light frost because temperatures at 28 °F can damage or kill vegetation that survives a 32 °F frost. The interval between the two 32°F 50% dates—April 1 and November 2—spans 216 days, giving gardeners a long window between the points of even odds for 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 April 24" 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 15" 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, WANumbered nearest stations: 1 — Bellingham (Airport), WA — 5 mi; 2 — Clearbrook, WA — 19 mi; 3 — Coupeville, WA — 36 mi; 4 — Concrete PPL Fish Station, WA — 37 mi; 5 — Upper Baker Dam, WA — 38 mi.WA25 mi · 40 km1. Bellingham (Airport), WA — 5 mi12. Clearbrook, WA — 19 mi23. Coupeville, WA — 36 mi34. Concrete PPL Fish Station, WA — 37 mi45. Upper Baker Dam, WA — 38 mi5
  1. Bellingham (Airport), WA 5 mi (9 km)
  2. Clearbrook, WA 19 mi (31 km)
  3. Coupeville, WA 36 mi (58 km)
  4. Concrete PPL Fish Station, WA 37 mi (60 km)
  5. Upper Baker Dam, WA 38 mi (61 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: 48.7178, -122.5114.