U.S. Frost Dates by Weather Station

NOAA station USC00368073 · Pennsylvania

Frost Dates for Shippensburg, PA

NOAA weather station Shippensburg (USC00368073), Pennsylvania · elevation 680 ft (207 m) · hardiness zone 7a*

  • Lower-risk planting dateafter May 6only 1 spring in 10 still has a frost later
  • Typical last frostApril 1950% chance of a frost after it
  • Typical first fall frostOctober 2450% chance of a frost before it
  • Frost-free season188 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Shippensburg, PASpring: a frost after April 4 in 9 years out of 10, after April 19 in half of the years, after May 6 in 1 year out of 10. Fall: the first frost comes before October 9 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: 188 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 19First frost ~Oct 24Frost season at Shippensburg, PASpring: a frost after April 4 in 9 years out of 10, after April 19 in half of the years, after May 6 in 1 year out of 10. Fall: the first frost comes before October 9 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: 188 days.JFMAMJJASONDLast frost ~Apr 19First 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)May 6October 9
50% (typical)April 19October 24
90% (likely)April 4November 6
Frost-free season (32°F, 50% chance)
188 days
Hard frost (28°F), last in spring, 50% chance after
April 5
Hard frost (28°F), first in fall, 50% chance before
November 4

The last 15 years (2006–2020 normals)

Typical last frost April 18 (1 day earlier than the 30-year normal), typical first fall frost October 27 (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 Shippensburg: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 6, 20% April 30, 30% April 25, 40% April 22, 50% April 19, 60% April 16, 70% April 12, 80% April 8, 90% April 4. Observed last spring frost in recent years: 2021 April 23, 2022 April 30, 2023 April 25, 2024 April 22, 2025 April 9, 2026 April 21.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 6Apr 19Apr 42021: April 232022: April 302023: April 252024: April 222025: April 92026: April 21Fall at Shippensburg: chance of a frost before this dateFall, chance of a frost before the date: 10% October 9, 20% October 13, 30% October 17, 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: 2021 November 2, 2022 October 21, 2023 October 31, 2024 October 17, 2025 October 26.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 9Oct 24Nov 62021: November 22022: October 212023: October 312024: October 172025: October 26
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 2
2022April 30October 21
2023April 25October 31
2024April 22October 17
2025April 9October 26
2026April 21season not over yet

What these dates mean

May 6 is the cautious spring date for setting out tender crops in Shippensburg; only a 10 % chance of a light frost remains after that day, so a gardener can plan to transplant seedlings with relatively low risk. The earlier date of April 4 carries a 90 % chance of a frost later, making it a gamble, while the median April 19 marks the point at which a light frost is equally likely to have occurred or not.

The 50 % light-frost dates—April 19 in spring and October 24 in fall—indicate the midpoint of the frost probability curve, meaning a garden-wide risk is split evenly around those days. October 9 is the cautious fall date for finishing harvest of tender crops, with only a 10 % chance that a light frost has arrived earlier. A hard frost at 28 °F can injure or kill plants that would otherwise survive a 32 °F light frost, so the hard-frost dates (April 5 and November 4) represent a more severe threshold.

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 9" 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 Shippensburg, PANumbered nearest stations: 1 — Chambersburg, PA — 11 mi; 2 — Biglerville, PA — 17 mi; 3 — Emmitsburg, MD — 29 mi; 4 — Lewistown, PA — 37 mi; 5 — near Middletown, PA — 41 mi.PAMDDE25 mi · 40 km1. Chambersburg, PA — 11 mi12. Biglerville, PA — 17 mi23. Emmitsburg, MD — 29 mi34. Lewistown, PA — 37 mi45. near Middletown, PA — 41 mi5
  1. Chambersburg, PA 11 mi (17 km)
  2. Biglerville, PA 17 mi (27 km)
  3. Emmitsburg, MD 29 mi (47 km)
  4. Lewistown, PA 37 mi (59 km)
  5. near Middletown, PA 41 mi (66 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: 40.0592, -77.5214.