U.S. Frost Dates by Weather Station

NOAA station USC00368469 · Pennsylvania

Frost Dates for Stevenson Dam, PA

NOAA weather station Stevenson Dam (USC00368469), Pennsylvania · elevation 932 ft (284 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 27only 1 spring in 10 still has a frost later
  • Typical last frostMay 1050% chance of a frost after it
  • Typical first fall frostOctober 1650% chance of a frost before it
  • Frost-free season157 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Stevenson Dam, PASpring: a frost after April 25 in 9 years out of 10, after May 10 in half of the years, after May 27 in 1 year out of 10. Fall: the first frost comes before October 2 in 1 year out of 10, before October 16 in half of the years, before October 30 in 9 years out of 10. Typical frost-free season: 157 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 10First frost ~Oct 16Frost season at Stevenson Dam, PASpring: a frost after April 25 in 9 years out of 10, after May 10 in half of the years, after May 27 in 1 year out of 10. Fall: the first frost comes before October 2 in 1 year out of 10, before October 16 in half of the years, before October 30 in 9 years out of 10. Typical frost-free season: 157 days.JFMAMJJASONDLast frost ~May 10First frost ~Oct 16
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 27October 2
50% (typical)May 10October 16
90% (likely)April 25October 30
Frost-free season (32°F, 50% chance)
157 days
Hard frost (28°F), last in spring, 50% chance after
April 30
Hard frost (28°F), first in fall, 50% chance before
October 29

The last 15 years (2006–2020 normals)

Typical last frost May 11 (1 day later than the 30-year normal), typical first fall frost October 19 (3 days later). Frost-free season 160 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 Stevenson Dam: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 27, 20% May 22, 30% May 17, 40% May 13, 50% May 10, 60% May 6, 70% May 3, 80% April 30, 90% April 25. Observed last spring frost in recent years: 2021 May 14, 2022 May 9, 2023 May 19, 2024 April 27, 2025 April 18, 2026 May 13.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 27May 10Apr 252021: May 142022: May 92023: May 192024: April 272025: April 182026: May 13Fall at Stevenson Dam: chance of a frost before this dateFall, chance of a frost before the date: 10% October 2, 20% October 6, 30% October 10, 40% October 13, 50% October 16, 60% October 19, 70% October 22, 80% October 26, 90% October 30. Observed first fall frost in recent years: 2021 November 3, 2022 October 18, 2023 October 23, 2024 October 17, 2025 October 10.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 2Oct 16Oct 302021: November 32022: October 182023: October 232024: October 172025: 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
2021May 14November 3
2022May 9October 18
2023May 19October 23
2024April 27October 17
2025April 18October 10
2026May 13season not over yet

What these dates mean

May 27 is the cautious spring date for setting out tender crops in Stevenson Dam, allowing a gardener to plant with only a 10 % chance of a later frost. The earlier spring date, April 25, carries a 90 % chance of a frost later and is therefore a gamble. The 50% spring date is May 10, indicating an even odds chance of a light frost later.

In the autumn, October 2 serves as the cautious fall date to finish harvesting tender crops, because there is only a 10 % chance that a frost has arrived earlier. The 50% fall date is October 16, marking an even odds chance of a light frost earlier, while October 30 carries a 90 % chance of an earlier frost and is risky. The hard-frost 50% dates are April 30 in spring and October 29 in fall; a hard frost at 28 °F can damage or kill plant tissue that survives a light frost at 32 °F.

How to read the probabilities

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

  • Spring: "10% after May 27" 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 2" 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 Stevenson Dam, PANumbered nearest stations: 1 — Renovo, PA — 15 mi; 2 — Lock Haven, PA — 36 mi; 3 — Ridgway, PA — 38 mi; 4 — Bradford, PA — 42 mi; 5 — State College, PA — 43 mi.PANY25 mi · 40 km1. Renovo, PA — 15 mi12. Lock Haven, PA — 36 mi23. Ridgway, PA — 38 mi34. Bradford, PA — 42 mi45. State College, PA — 43 mi5
  1. Renovo, PA 15 mi (25 km)
  2. Lock Haven, PA 36 mi (58 km)
  3. Ridgway, PA 38 mi (61 km)
  4. Bradford, PA 42 mi (68 km)
  5. State College, PA 43 mi (69 km)

Sources

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

Station coordinates: 41.4039, -78.0183.