U.S. Frost Dates by Weather Station

NOAA station USC00369050 · Pennsylvania

Frost Dates for Uniontown, PA

NOAA weather station Uniontown 1 NE (USC00369050), Pennsylvania · elevation 956 ft (291 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 18only 1 spring in 10 still has a frost later
  • Typical last frostApril 3050% chance of a frost after it
  • Typical first fall frostOctober 1850% chance of a frost before it
  • Frost-free season171 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Uniontown, PASpring: a frost after April 15 in 9 years out of 10, after April 30 in half of the years, after May 18 in 1 year out of 10. Fall: the first frost comes before October 5 in 1 year out of 10, before October 18 in half of the years, before October 30 in 9 years out of 10. Typical frost-free season: 171 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 30First frost ~Oct 18Frost season at Uniontown, PASpring: a frost after April 15 in 9 years out of 10, after April 30 in half of the years, after May 18 in 1 year out of 10. Fall: the first frost comes before October 5 in 1 year out of 10, before October 18 in half of the years, before October 30 in 9 years out of 10. Typical frost-free season: 171 days.JFMAMJJASONDLast frost ~Apr 30First frost ~Oct 18
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 26 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 18October 5
50% (typical)April 30October 18
90% (likely)April 15October 30
Frost-free season (32°F, 50% chance)
171 days
Hard frost (28°F), last in spring, 50% chance after
April 17
Hard frost (28°F), first in fall, 50% chance before
October 28

The last 15 years (2006–2020 normals)

Typical last frost April 27 (3 days earlier than the 30-year normal), typical first fall frost October 24 (6 days later). Frost-free season 177 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 Uniontown: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 18, 20% May 12, 30% May 7, 40% May 3, 50% April 30, 60% April 27, 70% April 24, 80% April 20, 90% April 15.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Jun 1May 18Apr 30Apr 15Fall at Uniontown: chance of a frost before this dateFall, chance of a frost before the date: 10% October 5, 20% October 9, 30% October 12, 40% October 15, 50% October 18, 60% October 21, 70% October 23, 80% October 26, 90% October 30.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 5Oct 18Oct 30
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.

What these dates mean

May 18, with a 10% chance of a light frost later, is the cautious date for setting out tender crops in Uniontown. Planting after this date gives a gardener a low-risk window to move seedlings into the garden.

April 30 is the 50% date for spring light frost, meaning there is an even chance of a frost after that point, while October 18 is the 50% date for fall light frost, indicating an even chance of a frost before then. The hard-frost median dates are April 17 in spring and October 28 in fall; a hard frost at 28 °F can damage plants more severely than a light frost at 32 °F, so it is a more critical threshold.

October 5, with only a 10% chance that a light frost has arrived earlier, is the cautious date for finishing the harvest of tender crops. Using these dates helps a gardener align planting and harvesting to the periods of lowest frost risk in this 26-year record.

How to read the probabilities

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

  • Spring: "10% after May 18" 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 5" 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 Uniontown, PANumbered nearest stations: 1 — near Morgantown, WV — 22 mi; 2 — Waynesburg, PA — 24 mi; 3 — McKeesport, PA — 30 mi; 4 — Fairmont, WV — 39 mi; 5 — Oakland, MD — 39 mi.PAOHMDVA25 mi · 40 km1. near Morgantown, WV — 22 mi12. Waynesburg, PA — 24 mi23. McKeesport, PA — 30 mi34. Fairmont, WV — 39 mi45. Oakland, MD — 39 mi5
  1. near Morgantown, WV 22 mi (35 km)
  2. Waynesburg, PA 24 mi (38 km)
  3. McKeesport, PA 30 mi (49 km)
  4. Fairmont, WV 39 mi (62 km)
  5. Oakland, MD 39 mi (62 km)

Sources

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

Station coordinates: 39.915, -79.7192.