U.S. Frost Dates by Weather Station

NOAA station USC00357823 · Oregon

Frost Dates for Silverton, OR

NOAA weather station Silverton (USC00357823), Oregon · elevation 408 ft (124 m) · hardiness zone 8b*

  • Lower-risk planting dateafter April 19only 1 spring in 10 still has a frost later
  • Typical last frostMarch 2850% chance of a frost after it
  • Typical first fall frostNovember 1050% chance of a frost before it
  • Frost-free season227 daystypical year, 32°F
  • Hardiness zone8bcalculated*

The year at a glance

Frost season at Silverton, ORSpring: a frost after March 1 in 9 years out of 10, after March 28 in half of the years, after April 19 in 1 year out of 10. Fall: the first frost comes before October 25 in 1 year out of 10, before November 10 in half of the years, before December 1 in 9 years out of 10. Typical frost-free season: 227 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Mar 28First frost ~Nov 10Frost season at Silverton, ORSpring: a frost after March 1 in 9 years out of 10, after March 28 in half of the years, after April 19 in 1 year out of 10. Fall: the first frost comes before October 25 in 1 year out of 10, before November 10 in half of the years, before December 1 in 9 years out of 10. Typical frost-free season: 227 days.JFMAMJJASONDLast frost ~Mar 28First frost ~Nov 10
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 19October 25
50% (typical)March 28November 10
90% (likely)March 1December 1
Frost-free season (32°F, 50% chance)
227 days
Hard frost (28°F), last in spring, 50% chance after
February 25
Hard frost (28°F), first in fall, 50% chance before
November 28

The last 15 years (2006–2020 normals)

Typical last frost March 27 (1 day earlier than the 30-year normal), typical first fall frost November 15 (5 days later). Frost-free season 233 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 Silverton: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 19, 20% April 10, 30% April 4, 40% March 31, 50% March 28, 60% March 23, 70% March 17, 80% March 10, 90% March 1. Observed last spring frost in recent years: 2021 March 30, 2022 April 15, 2023 March 27, 2024 March 14, 2025 March 18.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1May 1Apr 19Mar 28Mar 12021: March 302022: April 152023: March 272024: March 142025: March 18Fall at Silverton: chance of a frost before this dateFall, chance of a frost before the date: 10% October 25, 20% October 29, 30% November 2, 40% November 7, 50% November 10, 60% November 13, 70% November 19, 80% November 24, 90% December 1. Observed first fall frost in recent years: 2022 November 8, 2023 October 28, 2024 November 27.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Oct 25Nov 10Dec 12022: November 82023: October 282024: November 27
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
2021March 30incomplete record
2022April 15November 8
2023March 27October 28
2024March 14November 27
2025March 18incomplete record
2026incomplete recordseason not over yet

What these dates mean

The 227 days between the 50% dates in Silverton define the period in which most garden work can be scheduled. The 50% date is March 28, indicating a 50 % chance of a light frost later than this day, and the 50% date is November 10, indicating a 50 % chance of a light frost earlier than this day.

In spring the cautious date for setting out tender crops is April 19, when only a 10 % chance of a light frost remains; planting on March 1 carries a 90 % chance of frost and is therefore a gamble. In fall the cautious date to finish harvesting tender crops is October 25, with only a 10 % chance that a light frost has already arrived; waiting until December 1 involves a 90 % chance of frost and is a gamble.

Hard frost at 28 °F, with median dates of February 25 in spring and November 28 in fall, matters more than a 32 °F light frost because it can injure or kill plants that would otherwise survive the milder temperature.

How to read the probabilities

The dates are probabilities from 30 years of weather, not a forecast for this year.

  • Spring: "10% after April 19" 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 25" 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 Silverton, ORNumbered nearest stations: 1 — Stayton, OR — 15 mi; 2 — Dallas, OR — 26 mi; 3 — Lacomb, OR — 26 mi; 4 — Estacada, OR — 29 mi; 5 — near Corvallis, OR — 33 mi.WA25 mi · 40 km1. Stayton, OR — 15 mi12. Dallas, OR — 26 mi23. Lacomb, OR — 26 mi34. Estacada, OR — 29 mi45. near Corvallis, OR — 33 mi5
  1. Stayton, OR 15 mi (24 km)
  2. Dallas, OR 26 mi (41 km)
  3. Lacomb, OR 26 mi (43 km)
  4. Estacada, OR 29 mi (46 km)
  5. near Corvallis, OR 33 mi (53 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: 45.0058, -122.7739.