U.S. Frost Dates by Weather Station

NOAA station USC00347390 · Oklahoma

Frost Dates for Ralston, OK

NOAA weather station Ralston (USC00347390), Oklahoma · elevation 825 ft (252 m) · hardiness zone 7a*

  • Lower-risk planting dateafter April 27only 1 spring in 10 still has a frost later
  • Typical last frostApril 1150% chance of a frost after it
  • Typical first fall frostOctober 2450% chance of a frost before it
  • Frost-free season196 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Ralston, OKSpring: a frost after March 26 in 9 years out of 10, after April 11 in half of the years, after April 27 in 1 year out of 10. Fall: the first frost comes before October 7 in 1 year out of 10, before October 24 in half of the years, before November 6 in 9 years out of 10. Typical frost-free season: 196 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 11First frost ~Oct 24Frost season at Ralston, OKSpring: a frost after March 26 in 9 years out of 10, after April 11 in half of the years, after April 27 in 1 year out of 10. Fall: the first frost comes before October 7 in 1 year out of 10, before October 24 in half of the years, before November 6 in 9 years out of 10. Typical frost-free season: 196 days.JFMAMJJASONDLast frost ~Apr 11First frost ~Oct 24
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 27October 7
50% (typical)April 11October 24
90% (likely)March 26November 6
Frost-free season (32°F, 50% chance)
196 days
Hard frost (28°F), last in spring, 50% chance after
March 31
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 12 (1 day later than the 30-year normal), typical first fall frost October 25 (1 day later). Frost-free season 196 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 Ralston: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 27, 20% April 22, 30% April 17, 40% April 14, 50% April 11, 60% April 8, 70% April 4, 80% March 31, 90% March 26. Observed last spring frost in recent years: 2023 April 25, 2026 March 18.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 27Apr 11Mar 262023: April 252026: March 18Fall at Ralston: chance of a frost before this dateFall, chance of a frost before the date: 10% October 7, 20% October 14, 30% October 18, 40% October 21, 50% October 24, 60% October 27, 70% October 30, 80% November 1, 90% November 6. Observed first fall frost in recent years: 2023 October 18.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 7Oct 24Nov 62023: October 18
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 recordincomplete record
2022incomplete recordincomplete record
2023April 25October 18
2024incomplete recordincomplete record
2025incomplete recordincomplete record
2026March 18season not over yet

What these dates mean

April 27 is the cautious spring light-frost date in Ralston; with only a 10 % chance of a frost later, it lets a gardener set out tender crops with confidence. By contrast, the 90 % chance on March 26 makes an earlier planting a gamble. The 50 % date, April 11, marks the point where a light frost is equally likely to occur later.

For the harvest season, October 7 is the cautious fall light-frost date, giving a 10 % chance that a frost has already arrived and allowing tender crops to be finished. The 90 % chance on November 6 signals a risky extension. The median light-frost date, October 24, indicates an even-odds of frost earlier than that day. Hard-frost median dates are March 31 in spring and November 1 in fall; because 28 °F can damage plants more severely than 32 °F, hard frost is a more critical concern.

How to read the probabilities

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

  • Spring: "10% after April 27" 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 7" 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 Ralston, OKNumbered nearest stations: 1 — Ponca City, OK — 26 mi; 2 — Billings, OK — 39 mi; 3 — near Bartlesville, OK — 44 mi; 4 — Tulsa, OK — 52 mi; 5 — Sedan, KS — 53 mi.KS25 mi · 40 km1. Ponca City, OK — 26 mi12. Billings, OK — 39 mi23. near Bartlesville, OK — 44 mi34. Tulsa, OK — 52 mi45. Sedan, KS — 53 mi5
  1. Ponca City, OK 26 mi (41 km)
  2. Billings, OK 39 mi (63 km)
  3. near Bartlesville, OK 44 mi (70 km)
  4. Tulsa, OK 52 mi (84 km)
  5. Sedan, KS 53 mi (86 km)

Sources

* Hardiness zone 7a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 36.5044, -96.7439.