U.S. Frost Dates by Weather Station

NOAA station USW00004751 · Pennsylvania

Frost Dates for Bradford, PA

NOAA weather station Bradford Regional Airport (USW00004751), Pennsylvania · elevation 2117 ft (645 m) · hardiness zone 5b*

  • Lower-risk planting dateafter May 31only 1 spring in 10 still has a frost later
  • Typical last frostMay 1850% chance of a frost after it
  • Typical first fall frostOctober 150% chance of a frost before it
  • Frost-free season136 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Bradford, PASpring: a frost after April 30 in 9 years out of 10, after May 18 in half of the years, after May 31 in 1 year out of 10. Fall: the first frost comes before September 18 in 1 year out of 10, before October 1 in half of the years, before October 15 in 9 years out of 10. Typical frost-free season: 136 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 18First frost ~Oct 1Frost season at Bradford, PASpring: a frost after April 30 in 9 years out of 10, after May 18 in half of the years, after May 31 in 1 year out of 10. Fall: the first frost comes before September 18 in 1 year out of 10, before October 1 in half of the years, before October 15 in 9 years out of 10. Typical frost-free season: 136 days.JFMAMJJASONDLast frost ~May 18First frost ~Oct 1
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.Today

Frost dates (32°F)

Probability of frost, based on 27 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 31September 18
50% (typical)May 18October 1
90% (likely)April 30October 15
Frost-free season (32°F, 50% chance)
136 days
Hard frost (28°F), last in spring, 50% chance after
May 3
Hard frost (28°F), first in fall, 50% chance before
October 14

The last 15 years (2006–2020 normals)

Typical last frost May 15 (3 days earlier than the 30-year normal), typical first fall frost October 4 (3 days later). Frost-free season 140 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 Bradford: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 31, 20% May 27, 30% May 24, 40% May 21, 50% May 18, 60% May 14, 70% May 10, 80% May 5, 90% April 30. Observed last spring frost in recent years: 2021 May 15, 2022 April 30, 2023 May 26, 2024 May 11, 2025 June 2, 2026 May 12.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 31May 18Apr 302021: May 152022: April 302023: May 262024: May 112025: June 22026: May 12Fall at Bradford: chance of a frost before this dateFall, chance of a frost before the date: 10% September 18, 20% September 23, 30% September 26, 40% September 29, 50% October 1, 60% October 3, 70% October 6, 80% October 10, 90% October 15. Observed first fall frost in recent years: 2021 October 19, 2022 September 30, 2023 October 23, 2024 October 11, 2025 October 9.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 18Oct 1Oct 152021: October 192022: September 302023: October 232024: October 112025: October 9
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 15October 19
2022April 30September 30
2023May 26October 23
2024May 11October 11
2025June 2October 9
2026May 12season not over yet

What these dates mean

The cautious fall date for finishing the harvest in Bradford is September 18, when there is only a 10 % chance that a light frost has arrived.

For a Bradford gardener, the 50 % dates mark the point where a light frost is equally likely to have occurred or not. The 32 °F median dates are May 18 in spring and October 1 in fall; the 28 °F median dates are May 3 and October 14. These dates give a clear reference for the balance of risk.

A cautious planting plan uses the May 31 light-frost date in spring and the September 18 light-frost date in fall, each carrying only a 10 % chance of frost. Because a hard frost at 28 °F can damage plants more severely than a light frost at 32 °F, the hard-frost median dates are useful for assessing the deeper freeze risk.

How to read the probabilities

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

  • Spring: "10% after May 31" 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 September 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 Bradford, PANumbered nearest stations: 1 — Bradford 4 SW Research 5, PA — 8 mi; 2 — Kane, PA — 12 mi; 3 — near Allegany, NY — 21 mi; 4 — Warren, PA — 26 mi; 5 — Ridgway, PA — 27 mi.NY25 mi · 40 km1. Bradford 4 SW Research 5, PA — 8 mi12. Kane, PA — 12 mi23. near Allegany, NY — 21 mi34. Warren, PA — 26 mi45. Ridgway, PA — 27 mi5
  1. Bradford 4 SW Research 5, PA 8 mi (12 km)
  2. Kane, PA 12 mi (20 km)
  3. near Allegany, NY 21 mi (34 km)
  4. Warren, PA 26 mi (42 km)
  5. Ridgway, PA 27 mi (44 km)

Sources

* Hardiness zone 5b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 41.8031, -78.6403.