U.S. Frost Dates by Weather Station

NOAA station USW00094185 · Oregon

Frost Dates for Burns, OR

NOAA weather station Burns Municipal Airport (USW00094185), Oregon · elevation 4140 ft (1262 m) · hardiness zone 5b*

  • Lower-risk planting dateafter June 28only 1 spring in 10 still has a frost later
  • Typical last frostJune 1150% chance of a frost after it
  • Typical first fall frostSeptember 650% chance of a frost before it
  • Frost-free season85 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Burns, ORSpring: a frost after May 21 in 9 years out of 10, after June 11 in half of the years, after June 28 in 1 year out of 10. Fall: the first frost comes before August 21 in 1 year out of 10, before September 6 in half of the years, before September 20 in 9 years out of 10. Typical frost-free season: 85 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Jun 11First frost ~Sep 6Frost season at Burns, ORSpring: a frost after May 21 in 9 years out of 10, after June 11 in half of the years, after June 28 in 1 year out of 10. Fall: the first frost comes before August 21 in 1 year out of 10, before September 6 in half of the years, before September 20 in 9 years out of 10. Typical frost-free season: 85 days.JFMAMJJASONDLast frost ~Jun 11First frost ~Sep 6
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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)June 28August 21
50% (typical)June 11September 6
90% (likely)May 21September 20
Frost-free season (32°F, 50% chance)
85 days
Hard frost (28°F), last in spring, 50% chance after
May 20
Hard frost (28°F), first in fall, 50% chance before
September 19

The last 15 years (2006–2020 normals)

Typical last frost June 9 (2 days earlier than the 30-year normal), typical first fall frost September 9 (3 days later). Frost-free season 96 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 Burns: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 28, 20% June 23, 30% June 19, 40% June 15, 50% June 11, 60% June 8, 70% June 4, 80% May 30, 90% May 21. Observed last spring frost in recent years: 2021 June 7, 2022 June 19, 2023 June 21, 2024 June 18, 2025 June 23, 2026 June 28.Spring: last frostChance of a frost after this date10%50%90%Jun 1Jul 1Jun 28Jun 11May 212021: June 72022: June 192023: June 212024: June 182025: June 232026: June 28Fall at Burns: chance of a frost before this dateFall, chance of a frost before the date: 10% August 21, 20% August 28, 30% September 1, 40% September 3, 50% September 6, 60% September 9, 70% September 13, 80% September 16, 90% September 20. Observed first fall frost in recent years: 2021 August 22, 2022 September 9, 2023 September 14, 2024 September 21, 2025 August 8.Fall: first frostChance of a frost before this date10%50%90%Aug 1Sep 1Oct 1Aug 21Sep 6Sep 202021: August 222022: September 92023: September 142024: September 212025: August 8
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
2021June 7August 22
2022June 19September 9
2023June 21September 14
2024June 18September 21
2025June 23August 8
2026June 28season not over yet

What these dates mean

In Burns, the cautious fall date for finishing the harvest is August 21, when there is only a 10 % chance that a light frost has arrived earlier. Gardeners can count on tender crops to be harvested through that day with relatively low frost risk.

The 50 % light-frost dates are June 11 in spring and September 6 in fall; on each of those days the odds of a frost later (spring) or earlier (fall) are exactly even. The 50 % hard-frost dates are May 20 in spring and September 19 in fall, indicating a fifty-fifty chance that temperatures will drop to 28 °F on either side of those points.

For setting out tender crops, the cautious spring date is June 28, which carries only a 10 % chance of a frost later, while the cautious fall date remains August 21 for wrapping up the harvest. Hard frost matters more than light frost because temperatures of 28 °F can injure plants that would survive 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 June 28" 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 August 21" 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 Burns, ORNumbered nearest stations: 1 — Barnes Station, OR — 67 mi; 2 — Rome, OR — 83 mi; 3 — Baker City, OR — 103 mi; 4 — Payette, ID — 106 mi; 5 — near Redmond, OR — 118 mi.ORID50 mi · 80 km1. Barnes Station, OR — 67 mi12. Rome, OR — 83 mi23. Baker City, OR — 103 mi34. Payette, ID — 106 mi45. near Redmond, OR — 118 mi5
  1. Barnes Station, OR 67 mi (108 km)
  2. Rome, OR 83 mi (133 km)
  3. Baker City, OR 103 mi (166 km)
  4. Payette, ID 106 mi (171 km)
  5. near Redmond, OR 118 mi (190 km)

Sources

* Hardiness zone 5b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 43.595, -118.9564.