U.S. Frost Dates by Weather Station

NOAA station USC00157510 · Kentucky

Frost Dates for Somerset, KY

NOAA weather station Somerset 2 N (USC00157510), Kentucky · elevation 1020 ft (311 m) · hardiness zone 7a*

  • Lower-risk planting dateafter April 25only 1 spring in 10 still has a frost later
  • Typical last frostApril 550% chance of a frost after it
  • Typical first fall frostOctober 3050% chance of a frost before it
  • Frost-free season206 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Somerset, KYSpring: a frost after March 21 in 9 years out of 10, after April 5 in half of the years, after April 25 in 1 year out of 10. Fall: the first frost comes before October 17 in 1 year out of 10, before October 30 in half of the years, before November 13 in 9 years out of 10. Typical frost-free season: 206 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 5First frost ~Oct 30Frost season at Somerset, KYSpring: a frost after March 21 in 9 years out of 10, after April 5 in half of the years, after April 25 in 1 year out of 10. Fall: the first frost comes before October 17 in 1 year out of 10, before October 30 in half of the years, before November 13 in 9 years out of 10. Typical frost-free season: 206 days.JFMAMJJASONDLast frost ~Apr 5First frost ~Oct 30
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 25October 17
50% (typical)April 5October 30
90% (likely)March 21November 13
Frost-free season (32°F, 50% chance)
206 days
Hard frost (28°F), last in spring, 50% chance after
March 25
Hard frost (28°F), first in fall, 50% chance before
November 9

The last 15 years (2006–2020 normals)

Typical last frost April 3 (2 days earlier than the 30-year normal), typical first fall frost November 1 (2 days later). 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 Somerset: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 25, 20% April 18, 30% April 12, 40% April 8, 50% April 5, 60% April 2, 70% March 30, 80% March 27, 90% March 21.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 25Apr 5Mar 21Fall at Somerset: chance of a frost before this dateFall, chance of a frost before the date: 10% October 17, 20% October 22, 30% October 25, 40% October 27, 50% October 30, 60% November 1, 70% November 4, 80% November 7, 90% November 13.Fall: first frostChance of a frost before this date10%50%90%Nov 1Oct 17Oct 30Nov 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.

What these dates mean

The 206 days between the 50% dates in Somerset frame the window when a light frost is as likely as not, with the 50% date of April 5 marking the midpoint of spring and October 30 marking the midpoint of fall. For a gardener, these dates indicate when the odds of a frost drop to 50 % and rise again, defining the central portion of the frost-free season.

The cautious spring date for setting out tender crops is April 25, which carries a 10 % chance of a later frost, while the cautious fall date to finish harvesting tender crops is October 17, which carries a 10 % chance of an earlier frost. A hard frost, recorded at 28 °F, can damage plant tissue more severely than a light frost at 32 °F, so the 50% hard-frost dates of March 25 and November 9 are useful reference points for extreme cold risk.

How to read the probabilities

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

  • Spring: "10% after April 25" 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 17" 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 Somerset, KYNumbered nearest stations: 1 — near London, KY — 30 mi; 2 — near Lexington, KY — 64 mi; 3 — Bardstown, KY — 64 mi; 4 — Norris, TN — 70 mi; 5 — Tazewell, TN — 74 mi.KYTNVA50 mi · 80 km1. near London, KY — 30 mi12. near Lexington, KY — 64 mi23. Bardstown, KY — 64 mi34. Norris, TN — 70 mi45. Tazewell, TN — 74 mi5
  1. near London, KY 30 mi (48 km)
  2. near Lexington, KY 64 mi (103 km)
  3. Bardstown, KY 64 mi (103 km)
  4. Norris, TN 70 mi (112 km)
  5. Tazewell, TN 74 mi (119 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: 37.1167, -84.6167.