U.S. Frost Dates by Weather Station

NOAA station USC00364896 · Pennsylvania

Frost Dates for Lebanon, PA

NOAA weather station Lebanon 2 W (USC00364896), Pennsylvania · elevation 450 ft (137 m) · hardiness zone 7a*

  • Lower-risk planting dateafter May 7only 1 spring in 10 still has a frost later
  • Typical last frostApril 2050% chance of a frost after it
  • Typical first fall frostOctober 2550% chance of a frost before it
  • Frost-free season185 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Lebanon, PASpring: a frost after April 5 in 9 years out of 10, after April 20 in half of the years, after May 7 in 1 year out of 10. Fall: the first frost comes before October 10 in 1 year out of 10, before October 25 in half of the years, before November 6 in 9 years out of 10. Typical frost-free season: 185 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 20First frost ~Oct 25Frost season at Lebanon, PASpring: a frost after April 5 in 9 years out of 10, after April 20 in half of the years, after May 7 in 1 year out of 10. Fall: the first frost comes before October 10 in 1 year out of 10, before October 25 in half of the years, before November 6 in 9 years out of 10. Typical frost-free season: 185 days.JFMAMJJASONDLast frost ~Apr 20First frost ~Oct 25
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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 7October 10
50% (typical)April 20October 25
90% (likely)April 5November 6
Frost-free season (32°F, 50% chance)
185 days
Hard frost (28°F), last in spring, 50% chance after
April 4
Hard frost (28°F), first in fall, 50% chance before
November 5

The last 15 years (2006–2020 normals)

Typical last frost April 19 (1 day earlier than the 30-year normal), typical first fall frost October 28 (3 days later). Frost-free season 191 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 Lebanon: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 7, 20% May 1, 30% April 27, 40% April 23, 50% April 20, 60% April 17, 70% April 14, 80% April 10, 90% April 5. 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 7Apr 20Apr 52021: April 232022: April 302023: April 252024: April 222025: April 92026: April 21Fall at Lebanon: chance of a frost before this dateFall, chance of a frost before the date: 10% October 10, 20% October 15, 30% October 19, 40% October 22, 50% October 25, 60% October 28, 70% October 31, 80% November 2, 90% November 6. Observed first fall frost in recent years: 2021 November 3, 2022 October 21, 2023 November 1, 2024 October 17, 2025 October 25.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 10Oct 25Nov 62021: November 32022: October 212023: November 12024: October 172025: October 25
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 30October 21
2023April 25November 1
2024April 22October 17
2025April 9October 25
2026April 21season not over yet

What these dates mean

The cautious fall date in Lebanon for finishing the harvest is October 10, when there is only a 10 % chance that a light frost has arrived. In spring, the cautious date for setting out tender crops is May 7, which carries a 10 % chance of a frost later, while April 5 represents a 90 % chance and is a gamble.

The 50 % dates mark the point where a light frost is equally likely to have occurred or not; the median light-frost date is April 20 in spring and October 25 in fall. For hard frost, the 50 % dates are April 4 and November 5, indicating when a 28 °F freeze is as likely as not. A hard frost matters more than a light frost because the lower temperature can damage plant tissue that survives the milder 32 °F freeze.

How to read the probabilities

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

  • Spring: "10% after May 7" 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 Lebanon, PANumbered nearest stations: 1 — Landisville, PA — 15 mi; 2 — near Middletown, PA — 18 mi; 3 — near Lancaster, PA — 22 mi; 4 — near Whitfield, PA — 23 mi; 5 — New Holland, PA — 27 mi.PADE25 mi · 40 km1. Landisville, PA — 15 mi12. near Middletown, PA — 18 mi23. near Lancaster, PA — 22 mi34. near Whitfield, PA — 23 mi45. New Holland, PA — 27 mi5
  1. Landisville, PA 15 mi (24 km)
  2. near Middletown, PA 18 mi (30 km)
  3. near Lancaster, PA 22 mi (35 km)
  4. near Whitfield, PA 23 mi (38 km)
  5. New Holland, PA 27 mi (44 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: 40.3333, -76.4667.