U.S. Frost Dates by Weather Station

NOAA station USC00035018 · Arkansas

Frost Dates for Mountainburg, AR

NOAA weather station Mountainburg 2 NE (USC00035018), Arkansas · elevation 793 ft (242 m) · hardiness zone 7b*

  • Lower-risk planting dateafter April 28only 1 spring in 10 still has a frost later
  • Typical last frostApril 950% chance of a frost after it
  • Typical first fall frostOctober 2850% chance of a frost before it
  • Frost-free season201 daystypical year, 32°F
  • Hardiness zone7bcalculated*

The year at a glance

Frost season at Mountainburg, ARSpring: a frost after March 24 in 9 years out of 10, after April 9 in half of the years, after April 28 in 1 year out of 10. Fall: the first frost comes before October 14 in 1 year out of 10, before October 28 in half of the years, before November 12 in 9 years out of 10. Typical frost-free season: 201 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 9First frost ~Oct 28Frost season at Mountainburg, ARSpring: a frost after March 24 in 9 years out of 10, after April 9 in half of the years, after April 28 in 1 year out of 10. Fall: the first frost comes before October 14 in 1 year out of 10, before October 28 in half of the years, before November 12 in 9 years out of 10. Typical frost-free season: 201 days.JFMAMJJASONDLast frost ~Apr 9First frost ~Oct 28
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)April 28October 14
50% (typical)April 9October 28
90% (likely)March 24November 12
Frost-free season (32°F, 50% chance)
201 days
Hard frost (28°F), last in spring, 50% chance after
March 28
Hard frost (28°F), first in fall, 50% chance before
November 6

The last 15 years (2006–2020 normals)

Typical last frost April 7 (2 days earlier than the 30-year normal), typical first fall frost October 31 (3 days later). Frost-free season 205 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 Mountainburg: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 28, 20% April 21, 30% April 16, 40% April 13, 50% April 9, 60% April 6, 70% April 3, 80% March 30, 90% March 24.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 28Apr 9Mar 24Fall at Mountainburg: chance of a frost before this dateFall, chance of a frost before the date: 10% October 14, 20% October 19, 30% October 22, 40% October 25, 50% October 28, 60% October 31, 70% November 2, 80% November 6, 90% November 12. Observed first fall frost in recent years: 2021 November 5.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 14Oct 28Nov 122021: November 5
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
2021incomplete recordNovember 5
2022incomplete recordincomplete record
2023incomplete recordincomplete record
2024incomplete recordincomplete record
2025incomplete recordincomplete record
2026incomplete recordseason not over yet

What these dates mean

April 28 marks the cautious spring light-frost date in Mountainburg; with only a 10 % chance of a frost later, a gardener can plan to set out tender crops after that day. The opposite cautious fall date is October 14, when there is just a 10 % chance that a frost has arrived earlier, so harvesting tender crops can be safely finished by then.

The 50 % dates—April 9 for spring and October 28 for fall—represent the median point where a light frost is equally likely to occur later or earlier; they give a reference for the middle of the frost-free window. For hard frost, the median dates are March 28 in spring and November 6 in fall, indicating when a 28 °F frost is equally probable before or after. A hard frost matters more because the lower temperature can damage plants that 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 April 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 October 14" 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 Mountainburg, ARNumbered nearest stations: 1 — Ozark, AR — 19 mi; 2 — Fort Smith, AR — 25 mi; 3 — near Fayetteville, AR — 25 mi; 4 — Subiaco, AR — 38 mi; 5 — Blue Mountain Dam, AR — 47 mi.AROK25 mi · 40 km1. Ozark, AR — 19 mi12. Fort Smith, AR — 25 mi23. near Fayetteville, AR — 25 mi34. Subiaco, AR — 38 mi45. Blue Mountain Dam, AR — 47 mi5
  1. Ozark, AR 19 mi (30 km)
  2. Fort Smith, AR 25 mi (40 km)
  3. near Fayetteville, AR 25 mi (40 km)
  4. Subiaco, AR 38 mi (61 km)
  5. Blue Mountain Dam, AR 47 mi (75 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: 35.6494, -94.1542.