U.S. Frost Dates by Weather Station

NOAA station USC00367167 · Pennsylvania

Frost Dates near Patton, PA

NOAA weather station Prince Gallitzin State Park (USC00367167), Pennsylvania · elevation 1520 ft (463 m) · hardiness zone 6a*

Patton is the nearest town to the station (5.2 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter May 28only 1 spring in 10 still has a frost later
  • Typical last frostMay 1050% chance of a frost after it
  • Typical first fall frostOctober 550% chance of a frost before it
  • Frost-free season149 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season near Patton, PASpring: a frost after April 25 in 9 years out of 10, after May 10 in half of the years, after May 28 in 1 year out of 10. Fall: the first frost comes before September 24 in 1 year out of 10, before October 5 in half of the years, before October 21 in 9 years out of 10. Typical frost-free season: 149 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 10First frost ~Oct 5Frost season near Patton, PASpring: a frost after April 25 in 9 years out of 10, after May 10 in half of the years, after May 28 in 1 year out of 10. Fall: the first frost comes before September 24 in 1 year out of 10, before October 5 in half of the years, before October 21 in 9 years out of 10. Typical frost-free season: 149 days.JFMAMJJASONDLast frost ~May 10First frost ~Oct 5
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 27 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 28September 24
50% (typical)May 10October 5
90% (likely)April 25October 21
Frost-free season (32°F, 50% chance)
149 days
Hard frost (28°F), last in spring, 50% chance after
April 29
Hard frost (28°F), first in fall, 50% chance before
October 18

The last 15 years (2006–2020 normals)

Typical last frost May 7 (3 days earlier than the 30-year normal), typical first fall frost October 12 (7 days later). Frost-free season 153 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 near Patton: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 28, 20% May 24, 30% May 19, 40% May 14, 50% May 10, 60% May 6, 70% May 2, 80% April 29, 90% April 25. Observed last spring frost in recent years: 2023 May 26, 2024 April 23, 2025 April 28, 2026 May 12.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 28May 10Apr 252023: May 262024: April 232025: April 282026: May 12Fall near Patton: chance of a frost before this dateFall, chance of a frost before the date: 10% September 24, 20% September 28, 30% October 1, 40% October 3, 50% October 5, 60% October 9, 70% October 12, 80% October 15, 90% October 21. Observed first fall frost in recent years: 2023 October 23, 2024 October 11, 2025 October 9.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 24Oct 5Oct 212023: October 232024: October 112025: October 9
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
2023May 26October 23
2024April 23October 11
2025April 28October 9
2026May 12season not over yet

What these dates mean

Setting out tender crops on April 25 in the Patton area carries a 90% chance of a frost later than that date, making it a gamble for gardeners. A frost at that time could damage seedlings that have not yet hardened off.

The 50% spring date is May 10 and the 50% fall date is October 5; each represents an even chance of a light frost occurring on either side of the date, not a frost threshold.

For a cautious plan, tender crops are best placed outdoors after the May 28 light-frost date, which has only a 10% chance of a later frost, and are harvested before the September 24 light-frost date, which also has a 10% chance of an earlier frost. A hard frost at 28 °F, marked by the median dates April 29 in spring and October 18 in fall, can injure plants more severely than a light 32 °F frost.

How to read the probabilities

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

  • Spring: "10% after May 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 September 24" 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 Patton, PANumbered nearest stations: 1 — Altoona, PA — 12 mi; 2 — Ebensburg, PA — 16 mi; 3 — near Martinsburg, PA — 27 mi; 4 — Indiana, PA — 30 mi; 5 — State College, PA — 37 mi.25 mi · 40 km1. Altoona, PA — 12 mi12. Ebensburg, PA — 16 mi23. near Martinsburg, PA — 27 mi34. Indiana, PA — 30 mi45. State College, PA — 37 mi5
  1. Altoona, PA 12 mi (19 km)
  2. Ebensburg, PA 16 mi (25 km)
  3. near Martinsburg, PA 27 mi (44 km)
  4. Indiana, PA 30 mi (48 km)
  5. State College, PA 37 mi (60 km)

Sources

* Hardiness zone 6a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 40.6514, -78.555.