U.S. Frost Dates by Weather Station

NOAA station USC00350858 · Oregon

Frost Dates for Boardman, OR

NOAA weather station Boardman (USC00350858), Oregon · elevation 280 ft (85 m) · hardiness zone 7b*

  • Lower-risk planting dateafter May 2only 1 spring in 10 still has a frost later
  • Typical last frostApril 1450% chance of a frost after it
  • Typical first fall frostOctober 2150% chance of a frost before it
  • Frost-free season188 daystypical year, 32°F
  • Hardiness zone7bcalculated*

The year at a glance

Frost season at Boardman, ORSpring: a frost after March 28 in 9 years out of 10, after April 14 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 5 in 1 year out of 10, before October 21 in half of the years, before November 4 in 9 years out of 10. Typical frost-free season: 188 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 14First frost ~Oct 21Frost season at Boardman, ORSpring: a frost after March 28 in 9 years out of 10, after April 14 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 5 in 1 year out of 10, before October 21 in half of the years, before November 4 in 9 years out of 10. Typical frost-free season: 188 days.JFMAMJJASONDLast frost ~Apr 14First frost ~Oct 21
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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 2October 5
50% (typical)April 14October 21
90% (likely)March 28November 4
Frost-free season (32°F, 50% chance)
188 days
Hard frost (28°F), last in spring, 50% chance after
March 28
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 19 (5 days later than the 30-year normal), typical first fall frost October 20 (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 Boardman: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 2, 20% April 27, 30% April 23, 40% April 18, 50% April 14, 60% April 11, 70% April 8, 80% April 3, 90% March 28. Observed last spring frost in recent years: 2021 April 13, 2022 April 15, 2023 April 20, 2024 March 16, 2025 April 13.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 2Apr 14Mar 282021: April 132022: April 152023: April 202024: March 162025: April 13Fall at Boardman: chance of a frost before this dateFall, chance of a frost before the date: 10% October 5, 20% October 10, 30% October 14, 40% October 18, 50% October 21, 60% October 24, 70% October 26, 80% October 30, 90% November 4. Observed first fall frost in recent years: 2021 November 17, 2022 November 3, 2023 October 28, 2024 October 25.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 5Oct 21Nov 42021: November 172022: November 32023: October 282024: October 25
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 13November 17
2022April 15November 3
2023April 20October 28
2024March 16October 25
2025April 13incomplete record
2026incomplete recordseason not over yet

What these dates mean

Setting out tender crops on the early spring date, March 28, is a gamble in Boardman, because there is a 90 % chance of a light frost occurring later than that date. The same level of risk applies to a late-season gamble on November 4, when a light frost has a 90 % chance of arriving earlier.

A cautious planting schedule uses the May 2 date for spring tender crops, since only a 10 % chance of a light frost remains after it, and the October 5 date for finishing harvests in fall, when there is likewise only a 10 % chance that a light frost has come earlier. The 50 % dates—April 14 in spring and October 21 in fall—represent the point at which an even chance of a light frost exists later (spring) or earlier (fall).

Hard frosts at 28 °F are more threatening than light frosts at 32 °F; the hard-frost 50 % dates, March 28 and November 1, mark when there is an even chance of temperatures dropping to a level that can damage plants that would survive a 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 2" 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 5" 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 Boardman, ORNumbered nearest stations: 1 — Heppner, OR — 34 mi; 2 — Kennewick, WA — 38 mi; 3 — Richland, WA — 38 mi; 4 — Pendleton, OR — 42 mi; 5 — near Burbank, WA — 48 mi.ORWA25 mi · 40 km1. Heppner, OR — 34 mi12. Kennewick, WA — 38 mi23. Richland, WA — 38 mi34. Pendleton, OR — 42 mi45. near Burbank, WA — 48 mi5
  1. Heppner, OR 34 mi (55 km)
  2. Kennewick, WA 38 mi (61 km)
  3. Richland, WA 38 mi (61 km)
  4. Pendleton, OR 42 mi (67 km)
  5. near Burbank, WA 48 mi (77 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: 45.8472, -119.6933.