U.S. Frost Dates by Weather Station

NOAA station USW00014711 · Pennsylvania

Frost Dates near Middletown, PA

NOAA weather station Middletown Harrisburg International Airport (USW00014711), Pennsylvania · elevation 312 ft (95 m) · hardiness zone 7b*

Middletown is the nearest town to the station (1.7 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 April 25only 1 spring in 10 still has a frost later
  • Typical last frostApril 950% chance of a frost after it
  • Typical first fall frostNovember 250% chance of a frost before it
  • Frost-free season206 daystypical year, 32°F
  • Hardiness zone7bcalculated*

The year at a glance

Frost season near Middletown, PASpring: a frost after March 28 in 9 years out of 10, after April 9 in half of the years, after April 25 in 1 year out of 10. Fall: the first frost comes before October 18 in 1 year out of 10, before November 2 in half of the years, before November 15 in 9 years out of 10. Typical frost-free season: 206 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 9First frost ~Nov 2Frost season near Middletown, PASpring: a frost after March 28 in 9 years out of 10, after April 9 in half of the years, after April 25 in 1 year out of 10. Fall: the first frost comes before October 18 in 1 year out of 10, before November 2 in half of the years, before November 15 in 9 years out of 10. Typical frost-free season: 206 days.JFMAMJJASONDLast frost ~Apr 9First frost ~Nov 2
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)April 25October 18
50% (typical)April 9November 2
90% (likely)March 28November 15
Frost-free season (32°F, 50% chance)
206 days
Hard frost (28°F), last in spring, 50% chance after
March 30
Hard frost (28°F), first in fall, 50% chance before
November 14

The last 15 years (2006–2020 normals)

Typical last frost April 9 (same as the 30-year normal), typical first fall frost November 3 (1 day later). Frost-free season 207 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 Middletown: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 25, 20% April 18, 30% April 15, 40% April 11, 50% April 9, 60% April 7, 70% April 4, 80% April 1, 90% March 28. Observed last spring frost in recent years: 2021 April 23, 2022 April 11, 2023 April 9, 2024 March 26, 2025 April 9, 2026 April 21.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 25Apr 9Mar 282021: April 232022: April 112023: April 92024: March 262025: April 92026: April 21Fall near Middletown: chance of a frost before this dateFall, chance of a frost before the date: 10% October 18, 20% October 24, 30% October 27, 40% October 31, 50% November 2, 60% November 4, 70% November 7, 80% November 10, 90% November 15. Observed first fall frost in recent years: 2021 November 4, 2022 November 14, 2023 November 2, 2024 November 13, 2025 November 7.Fall: first frostChance of a frost before this date10%50%90%Nov 1Oct 18Nov 2Nov 152021: November 42022: November 142023: November 22024: November 132025: 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 11November 14
2023April 9November 2
2024March 26November 13
2025April 9November 7
2026April 21season not over yet

What these dates mean

April 25 is the cautious spring date for the Middletown area; with only a 10 % chance of a light frost after that day, a gardener can plan to set out tender crops with relatively low risk.

The 50% dates, April 9 for spring and November 2 for fall, represent the median point at which a light frost is equally likely to have occurred or not, and the interval between them spans 206 days of roughly equal frost probability. The median hard-frost dates are March 30 in spring and November 14 in fall, reminding that temperatures of 28 °F can damage plants more severely than the 32 °F light frost.

October 18 is the cautious fall date, carrying only a 10 % chance that a light frost has arrived earlier, so tender crops can be harvested or protected with confidence. Because a hard frost at 28 °F can cause more extensive injury than a light frost at 32 °F, it is a more critical threshold for plant survival.

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 18" 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 Middletown, PANumbered nearest stations: 1 — Lebanon, PA — 18 mi; 2 — Landisville, PA — 19 mi; 3 — near Lancaster, PA — 28 mi; 4 — Biglerville, PA — 32 mi; 5 — Millers, MD — 33 mi.MDDE25 mi · 40 km1. Lebanon, PA — 18 mi12. Landisville, PA — 19 mi23. near Lancaster, PA — 28 mi34. Biglerville, PA — 32 mi45. Millers, MD — 33 mi5
  1. Lebanon, PA 18 mi (30 km)
  2. Landisville, PA 19 mi (30 km)
  3. near Lancaster, PA 28 mi (45 km)
  4. Biglerville, PA 32 mi (51 km)
  5. Millers, MD 33 mi (53 km)

Sources

* Hardiness zone 7b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 40.1936, -76.7633.