U.S. Frost Dates by Weather Station

NOAA station USC00348042 · Oklahoma

Frost Dates for Seminole, OK

NOAA weather station Seminole (USC00348042), Oklahoma · elevation 924 ft (282 m) · hardiness zone 7b*

  • Lower-risk planting dateafter April 22only 1 spring in 10 still has a frost later
  • Typical last frostApril 550% chance of a frost after it
  • Typical first fall frostNovember 150% chance of a frost before it
  • Frost-free season210 daystypical year, 32°F
  • Hardiness zone7bcalculated*

The year at a glance

Frost season at Seminole, OKSpring: a frost after March 18 in 9 years out of 10, after April 5 in half of the years, after April 22 in 1 year out of 10. Fall: the first frost comes before October 18 in 1 year out of 10, before November 1 in half of the years, before November 15 in 9 years out of 10. Typical frost-free season: 210 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 5First frost ~Nov 1Frost season at Seminole, OKSpring: a frost after March 18 in 9 years out of 10, after April 5 in half of the years, after April 22 in 1 year out of 10. Fall: the first frost comes before October 18 in 1 year out of 10, before November 1 in half of the years, before November 15 in 9 years out of 10. Typical frost-free season: 210 days.JFMAMJJASONDLast frost ~Apr 5First frost ~Nov 1
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 25 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)April 22October 18
50% (typical)April 5November 1
90% (likely)March 18November 15
Frost-free season (32°F, 50% chance)
210 days
Hard frost (28°F), last in spring, 50% chance after
March 24
Hard frost (28°F), first in fall, 50% chance before
November 9

The last 15 years (2006–2020 normals)

Typical last frost April 2 (3 days earlier than the 30-year normal), typical first fall frost November 1. Frost-free season 211 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 Seminole: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 22, 20% April 17, 30% April 12, 40% April 8, 50% April 5, 60% April 2, 70% March 29, 80% March 25, 90% March 18.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 22Apr 5Mar 18Fall at Seminole: chance of a frost before this dateFall, chance of a frost before the date: 10% October 18, 20% October 23, 30% October 27, 40% October 30, 50% November 1, 60% November 4, 70% November 6, 80% November 10, 90% November 15.Fall: first frostChance of a frost before this date10%50%90%Nov 1Oct 18Nov 1Nov 15
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.

What these dates mean

April 22, the cautious spring date, gives a gardener a 10% chance of a light frost later and therefore a reliable point to set out tender crops. The 50% dates—April 5 in spring and November 1 in fall—mark the point where a light frost is equally likely to occur before or after, offering a statistical midpoint for planning. The hard-frost 50% dates are March 24 and November 9.

October 18, the cautious fall date, carries a 10% chance that a light frost has arrived earlier, so it marks a reliable window to finish harvesting tender crops. A hard frost at 28 °F can injure plant tissue that usually survives a light 32 °F frost, making it a more critical threshold. The data span 25 years, giving a robust basis for these probabilities.

How to read the probabilities

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

  • Spring: "10% after April 22" 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 18" 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 Seminole, OKNumbered nearest stations: 1 — Meeker, OK — 26 mi; 2 — near Oklahoma City, OK — 55 mi; 3 — McAlester, OK — 55 mi; 4 — Blanchard, OK — 58 mi; 5 — Madill, OK — 79 mi.OK25 mi · 40 km1. Meeker, OK — 26 mi12. near Oklahoma City, OK — 55 mi23. McAlester, OK — 55 mi34. Blanchard, OK — 58 mi45. Madill, OK — 79 mi5
  1. Meeker, OK 26 mi (42 km)
  2. near Oklahoma City, OK 55 mi (88 km)
  3. McAlester, OK 55 mi (88 km)
  4. Blanchard, OK 58 mi (93 km)
  5. Madill, OK 79 mi (127 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: 35.2317, -96.6531.