U.S. Frost Dates by Weather Station

NOAA station USC00360656 · Pennsylvania

Frost Dates for Biglerville, PA

NOAA weather station Biglerville (USC00360656), Pennsylvania · elevation 720 ft (220 m) · hardiness zone 7a*

  • Lower-risk planting dateafter May 4only 1 spring in 10 still has a frost later
  • Typical last frostApril 1550% chance of a frost after it
  • Typical first fall frostOctober 2750% chance of a frost before it
  • Frost-free season194 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Biglerville, PASpring: a frost after April 1 in 9 years out of 10, after April 15 in half of the years, after May 4 in 1 year out of 10. Fall: the first frost comes before October 11 in 1 year out of 10, before October 27 in half of the years, before November 10 in 9 years out of 10. Typical frost-free season: 194 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 15First frost ~Oct 27Frost season at Biglerville, PASpring: a frost after April 1 in 9 years out of 10, after April 15 in half of the years, after May 4 in 1 year out of 10. Fall: the first frost comes before October 11 in 1 year out of 10, before October 27 in half of the years, before November 10 in 9 years out of 10. Typical frost-free season: 194 days.JFMAMJJASONDLast frost ~Apr 15First frost ~Oct 27
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)May 4October 11
50% (typical)April 15October 27
90% (likely)April 1November 10
Frost-free season (32°F, 50% chance)
194 days
Hard frost (28°F), last in spring, 50% chance after
April 3
Hard frost (28°F), first in fall, 50% chance before
November 8

The last 15 years (2006–2020 normals)

Typical last frost April 14 (1 day earlier than the 30-year normal), typical first fall frost October 29 (2 days later). Frost-free season 196 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 Biglerville: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 4, 20% April 29, 30% April 22, 40% April 18, 50% April 15, 60% April 12, 70% April 9, 80% April 5, 90% April 1. Observed last spring frost in recent years: 2021 April 23, 2022 April 20, 2023 April 25, 2024 March 26, 2025 April 10, 2026 April 22.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 4Apr 15Apr 12021: April 232022: April 202023: April 252024: March 262025: April 102026: April 22Fall at Biglerville: chance of a frost before this dateFall, chance of a frost before the date: 10% October 11, 20% October 15, 30% October 20, 40% October 23, 50% October 27, 60% October 30, 70% November 2, 80% November 5, 90% November 10. Observed first fall frost in recent years: 2021 November 4, 2022 October 20, 2023 November 2, 2024 November 9, 2025 November 7.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 11Oct 27Nov 102021: November 42022: October 202023: November 22024: November 92025: November 7
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 4
2022April 20October 20
2023April 25November 2
2024March 26November 9
2025April 10November 7
2026April 22season not over yet

What these dates mean

May 4 is the cautious spring date for Biglerville, and it marks a point when only a 10 % chance of a light frost remains, allowing tender crops to be set out with minimal risk.

The 50 % date is April 15; at that moment there is an even chance of a light frost later in spring. The cautious fall date is October 11, when a light frost has only a 10 % chance of arriving earlier, giving gardeners a reference for finishing tender-crop harvests. The 50 % date is October 27, representing an even chance of a light frost earlier in fall. The hard-frost 50 % dates are April 3 and November 8, indicating the points at which a 28 °F frost is equally likely to have occurred or not.

A hard frost matters more than a light frost because the lower temperature can damage plant tissues that survive the milder 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 4" 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 11" 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 Biglerville, PANumbered nearest stations: 1 — Shippensburg, PA — 17 mi; 2 — Emmitsburg, MD — 18 mi; 3 — Chambersburg, PA — 20 mi; 4 — Millers, MD — 28 mi; 5 — near Middletown, PA — 32 mi.PAMDWV25 mi · 40 km1. Shippensburg, PA — 17 mi12. Emmitsburg, MD — 18 mi23. Chambersburg, PA — 20 mi34. Millers, MD — 28 mi45. near Middletown, PA — 32 mi5
  1. Shippensburg, PA 17 mi (27 km)
  2. Emmitsburg, MD 18 mi (29 km)
  3. Chambersburg, PA 20 mi (33 km)
  4. Millers, MD 28 mi (45 km)
  5. near Middletown, PA 32 mi (51 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: 39.9347, -77.2547.