U.S. Frost Dates by Weather Station

NOAA station USC00368449 · Pennsylvania

Frost Dates for State College, PA

NOAA weather station State College (USC00368449), Pennsylvania · elevation 1170 ft (357 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 6only 1 spring in 10 still has a frost later
  • Typical last frostApril 2050% chance of a frost after it
  • Typical first fall frostOctober 2650% chance of a frost before it
  • Frost-free season187 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at State College, PASpring: a frost after April 7 in 9 years out of 10, after April 20 in half of the years, after May 6 in 1 year out of 10. Fall: the first frost comes before October 10 in 1 year out of 10, before October 26 in half of the years, before November 9 in 9 years out of 10. Typical frost-free season: 187 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 20First frost ~Oct 26Frost season at State College, PASpring: a frost after April 7 in 9 years out of 10, after April 20 in half of the years, after May 6 in 1 year out of 10. Fall: the first frost comes before October 10 in 1 year out of 10, before October 26 in half of the years, before November 9 in 9 years out of 10. Typical frost-free season: 187 days.JFMAMJJASONDLast frost ~Apr 20First frost ~Oct 26
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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 6October 10
50% (typical)April 20October 26
90% (likely)April 7November 9
Frost-free season (32°F, 50% chance)
187 days
Hard frost (28°F), last in spring, 50% chance after
April 8
Hard frost (28°F), first in fall, 50% chance before
November 5

The last 15 years (2006–2020 normals)

Typical last frost April 18 (2 days earlier than the 30-year normal), typical first fall frost October 29 (3 days later). Frost-free season 192 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 State College: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 6, 20% May 1, 30% April 27, 40% April 23, 50% April 20, 60% April 18, 70% April 15, 80% April 12, 90% April 7. Observed last spring frost in recent years: 2021 April 23, 2022 April 29, 2023 April 25, 2024 April 22, 2025 April 17, 2026 April 22.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 6Apr 20Apr 72021: April 232022: April 292023: April 252024: April 222025: April 172026: April 22Fall at State College: chance of a frost before this dateFall, chance of a frost before the date: 10% October 10, 20% October 17, 30% October 20, 40% October 23, 50% October 26, 60% October 30, 70% November 1, 80% November 4, 90% November 9. Observed first fall frost in recent years: 2021 November 3, 2022 October 21, 2023 November 2, 2024 October 27, 2025 October 10.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 10Oct 26Nov 92021: November 32022: October 212023: November 22024: October 272025: October 10
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
2021April 23November 3
2022April 29October 21
2023April 25November 2
2024April 22October 27
2025April 17October 10
2026April 22season not over yet

What these dates mean

The 187 days between the 50% dates in State College and what fits into them give gardeners a clear window for tender crops. The median light-frost dates are April 20 in spring and October 26 in fall; at each of these dates the chance of a frost later (spring) or earlier (fall) is even.

For a low-risk schedule, the cautious spring date is May 6, when only a 10 % chance of a light frost remains, while the cautious fall date is October 10, with only a 10 % chance that a light frost has already arrived.

Hard-frost dates, April 8 and November 5, mark when temperatures can reach 28 °F, a level that can damage plants more severely than the 32 °F light-frost threshold. The 29-year record provides the statistical 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 May 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 10" 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 State College, PANumbered nearest stations: 1 — Lewistown, PA — 21 mi; 2 — Lock Haven, PA — 33 mi; 3 — near Patton, PA — 37 mi; 4 — Altoona, PA — 38 mi; 5 — Renovo, PA — 38 mi.25 mi · 40 km1. Lewistown, PA — 21 mi12. Lock Haven, PA — 33 mi23. near Patton, PA — 37 mi34. Altoona, PA — 38 mi45. Renovo, PA — 38 mi5
  1. Lewistown, PA 21 mi (34 km)
  2. Lock Haven, PA 33 mi (52 km)
  3. near Patton, PA 37 mi (60 km)
  4. Altoona, PA 38 mi (60 km)
  5. Renovo, PA 38 mi (61 km)

Sources

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

Station coordinates: 40.7933, -77.8672.