U.S. Frost Dates by Weather Station

NOAA station USC00033862 · Arkansas

Frost Dates for Keo, AR

NOAA weather station Keo (USC00033862), Arkansas · elevation 231 ft (70 m) · hardiness zone 8a*

  • Lower-risk planting dateafter April 6only 1 spring in 10 still has a frost later
  • Typical last frostMarch 2150% chance of a frost after it
  • Typical first fall frostNovember 950% chance of a frost before it
  • Frost-free season235 daystypical year, 32°F
  • Hardiness zone8acalculated*

The year at a glance

Frost season at Keo, ARSpring: a frost after March 2 in 9 years out of 10, after March 21 in half of the years, after April 6 in 1 year out of 10. Fall: the first frost comes before October 27 in 1 year out of 10, before November 9 in half of the years, before November 26 in 9 years out of 10. Typical frost-free season: 235 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Mar 21First frost ~Nov 9Frost season at Keo, ARSpring: a frost after March 2 in 9 years out of 10, after March 21 in half of the years, after April 6 in 1 year out of 10. Fall: the first frost comes before October 27 in 1 year out of 10, before November 9 in half of the years, before November 26 in 9 years out of 10. Typical frost-free season: 235 days.JFMAMJJASONDLast frost ~Mar 21First frost ~Nov 9
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)April 6October 27
50% (typical)March 21November 9
90% (likely)March 2November 26
Frost-free season (32°F, 50% chance)
235 days
Hard frost (28°F), last in spring, 50% chance after
March 8
Hard frost (28°F), first in fall, 50% chance before
November 22

The last 15 years (2006–2020 normals)

Typical last frost March 16 (5 days earlier than the 30-year normal), typical first fall frost November 10 (1 day later). Frost-free season 240 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 Keo: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 6, 20% April 1, 30% March 28, 40% March 24, 50% March 21, 60% March 18, 70% March 13, 80% March 9, 90% March 2. Observed last spring frost in recent years: 2021 February 23, 2022 March 12, 2024 February 21.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1Apr 6Mar 21Mar 22021: February 232022: March 122024: February 21Fall at Keo: chance of a frost before this dateFall, chance of a frost before the date: 10% October 27, 20% November 1, 30% November 3, 40% November 6, 50% November 9, 60% November 12, 70% November 16, 80% November 21, 90% November 26. Observed first fall frost in recent years: 2021 December 7, 2022 November 13.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Oct 27Nov 9Nov 262021: December 72022: November 13
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
2021February 23December 7
2022March 12November 13
2023incomplete recordincomplete record
2024February 21incomplete record
2025no datano data
2026no dataseason not over yet

What these dates mean

The 235 days between the 32°F 50% dates in Keo, March 21 and November 9, hold the window when tender crops can be grown without a light frost interrupting them. The 50% date in spring is March 21, a point at which a light frost later in the season is equally likely as not; the 50% date in fall is November 9, when a light frost earlier in the season is equally likely as not.

For a cautious spring planting schedule, the date to set out tender crops is April 6, which carries a 10 % chance of a frost later. In fall, the cautious date to finish harvesting tender crops is October 27, which carries a 10 % chance of a frost earlier. A hard frost at 28 °F, marked by the median dates of March 8 in spring and November 22 in fall, can damage plants more severely than a light frost at 32 °F.

How to read the probabilities

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

  • Spring: "10% after April 6" 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 27" 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 Keo, ARNumbered nearest stations: 1 — Little Rock (Adams Field), AR — 16 mi; 2 — Little Rock, AR — 22 mi; 3 — Pine Bluff, AR — 26 mi; 4 — Pine Bluff (Grider Field), AR — 30 mi; 5 — Sheridan, AR — 31 mi.ARMS25 mi · 40 km1. Little Rock (Adams Field), AR — 16 mi12. Little Rock, AR — 22 mi23. Pine Bluff, AR — 26 mi34. Pine Bluff (Grider Field), AR — 30 mi45. Sheridan, AR — 31 mi5
  1. Little Rock (Adams Field), AR 16 mi (26 km)
  2. Little Rock, AR 22 mi (36 km)
  3. Pine Bluff, AR 26 mi (42 km)
  4. Pine Bluff (Grider Field), AR 30 mi (48 km)
  5. Sheridan, AR 31 mi (50 km)

Sources

* Hardiness zone 8a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 34.6033, -91.9928.