U.S. Frost Dates by Weather Station

NOAA station USC00035866 · Arkansas

Frost Dates for Portland, AR

NOAA weather station Portland (USC00035866), Arkansas · elevation 128 ft (39 m) · hardiness zone 8b*

  • Lower-risk planting dateafter April 1only 1 spring in 10 still has a frost later
  • Typical last frostMarch 1450% chance of a frost after it
  • Typical first fall frostNovember 1050% chance of a frost before it
  • Frost-free season241 daystypical year, 32°F
  • Hardiness zone8bcalculated*

The year at a glance

Frost season at Portland, ARSpring: a frost after February 25 in 9 years out of 10, after March 14 in half of the years, after April 1 in 1 year out of 10. Fall: the first frost comes before October 28 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: 241 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Mar 14First frost ~Nov 10Frost season at Portland, ARSpring: a frost after February 25 in 9 years out of 10, after March 14 in half of the years, after April 1 in 1 year out of 10. Fall: the first frost comes before October 28 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: 241 days.JFMAMJJASONDLast frost ~Mar 14First 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 1October 28
50% (typical)March 14November 10
90% (likely)February 25December 1
Frost-free season (32°F, 50% chance)
241 days
Hard frost (28°F), last in spring, 50% chance after
March 2
Hard frost (28°F), first in fall, 50% chance before
November 25

The last 15 years (2006–2020 normals)

Typical last frost March 11 (3 days earlier than the 30-year normal), typical first fall frost November 12 (2 days later). Frost-free season 247 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 Portland: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 1, 20% March 27, 30% March 23, 40% March 18, 50% March 14, 60% March 11, 70% March 6, 80% March 1, 90% February 25. Observed last spring frost in recent years: 2021 March 3, 2022 March 14, 2023 March 21, 2024 February 19, 2025 February 23, 2026 March 19.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1Apr 1Mar 14Feb 252021: March 32022: March 142023: March 212024: February 192025: February 232026: March 19Fall at Portland: chance of a frost before this dateFall, chance of a frost before the date: 10% October 28, 20% November 1, 30% November 4, 40% November 7, 50% November 10, 60% November 14, 70% November 19, 80% November 24, 90% December 1. Observed first fall frost in recent years: 2021 November 14, 2022 October 19, 2023 November 1, 2024 November 30, 2025 November 10.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Oct 28Nov 10Dec 12021: November 142022: October 192023: November 12024: November 302025: November 10
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 3November 14
2022March 14October 19
2023March 21November 1
2024February 19November 30
2025February 23November 10
2026March 19season not over yet

What these dates mean

Planting tender crops on February 25 carries a 90% chance of a frost later than that date, making it a gamble for gardeners in Portland. The cautious date for setting out tender crops is April 1, when only a 10% chance of a later light frost remains. The 50% date is March 14, marking the point at which a light frost is equally likely to occur after it.

In the fall, finishing tender-crop harvest by October 28 leaves only a 10% chance that a light frost has arrived earlier, while waiting until December 1 involves a 90% chance of an earlier frost and is a gamble. The 50% date is November 10. Hard-frost median dates are March 2 and November 25; hard frost matters more than a 32 °F light frost because the lower temperature can cause more severe plant damage.

How to read the probabilities

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

  • Spring: "10% after April 1" 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 28" 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 Portland, ARNumbered nearest stations: 1 — Dermott, AR — 22 mi; 2 — Crossett, AR — 27 mi; 3 — Monticello, AR — 30 mi; 4 — Lake Providence, LA — 36 mi; 5 — Rohwer, AR — 41 mi.ARMSLA25 mi · 40 km1. Dermott, AR — 22 mi12. Crossett, AR — 27 mi23. Monticello, AR — 30 mi34. Lake Providence, LA — 36 mi45. Rohwer, AR — 41 mi5
  1. Dermott, AR 22 mi (36 km)
  2. Crossett, AR 27 mi (44 km)
  3. Monticello, AR 30 mi (49 km)
  4. Lake Providence, LA 36 mi (58 km)
  5. Rohwer, AR 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: 33.2511, -91.5058.