U.S. Frost Dates by Weather Station

NOAA station USC00367931 · Pennsylvania

Frost Dates for Selinsgrove, PA

NOAA weather station Selinsgrove 2 S (USC00367931), Pennsylvania · elevation 420 ft (128 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 10only 1 spring in 10 still has a frost later
  • Typical last frostApril 2550% chance of a frost after it
  • Typical first fall frostOctober 2250% chance of a frost before it
  • Frost-free season178 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Selinsgrove, PASpring: a frost after April 9 in 9 years out of 10, after April 25 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before October 7 in 1 year out of 10, before October 22 in half of the years, before November 3 in 9 years out of 10. Typical frost-free season: 178 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 25First frost ~Oct 22Frost season at Selinsgrove, PASpring: a frost after April 9 in 9 years out of 10, after April 25 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before October 7 in 1 year out of 10, before October 22 in half of the years, before November 3 in 9 years out of 10. Typical frost-free season: 178 days.JFMAMJJASONDLast frost ~Apr 25First frost ~Oct 22
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 10October 7
50% (typical)April 25October 22
90% (likely)April 9November 3
Frost-free season (32°F, 50% chance)
178 days
Hard frost (28°F), last in spring, 50% chance after
April 10
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 24 (1 day earlier than the 30-year normal), typical first fall frost October 24 (2 days later). Frost-free season 180 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 Selinsgrove: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 10, 20% May 6, 30% May 1, 40% April 28, 50% April 25, 60% April 20, 70% April 18, 80% April 14, 90% April 9. Observed last spring frost in recent years: 2021 April 24, 2022 May 9, 2023 April 25, 2024 April 23, 2025 April 17, 2026 April 22.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 10Apr 25Apr 92021: April 242022: May 92023: April 252024: April 232025: April 172026: April 22Fall at Selinsgrove: chance of a frost before this dateFall, chance of a frost before the date: 10% October 7, 20% October 12, 30% October 16, 40% October 19, 50% October 22, 60% October 24, 70% October 27, 80% October 30, 90% November 3. Observed first fall frost in recent years: 2021 November 3, 2022 October 21, 2023 November 1, 2024 October 18, 2025 October 27.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 7Oct 22Nov 32021: November 32022: October 212023: November 12024: October 182025: October 27
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 24November 3
2022May 9October 21
2023April 25November 1
2024April 23October 18
2025April 17October 27
2026April 22season not over yet

What these dates mean

Setting out tender crops on April 9 in Selinsgrove carries a 90 % chance of a light frost later in spring, so planting then is a gamble for gardeners. The cautious alternative is May 10, when only a 10 % chance of a later frost remains, offering a much lower risk for delicate seedlings.

The 50 % spring date of April 25 marks the point where a light frost is equally likely to occur before or after that day; similarly, October 22 is the 50 % fall date where a light frost is equally likely to have happened earlier or later. For a low-risk finish to tender-crop harvest, October 7 is the cautious fall date with only a 10 % chance that a light frost has arrived earlier. These median dates are not frost events themselves but serve as reference points for the probability curve.

A hard frost at 28 °F, indicated by the median dates April 10 and November 1, can damage plants more severely than a light 32 °F frost.

How to read the probabilities

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

  • Spring: "10% after May 10" 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 7" 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 Selinsgrove, PANumbered nearest stations: 1 — Williamsport, PA — 32 mi; 2 — Lebanon, PA — 37 mi; 3 — Lock Haven, PA — 38 mi; 4 — Lewistown, PA — 39 mi; 5 — near Middletown, PA — 41 mi.25 mi · 40 km1. Williamsport, PA — 32 mi12. Lebanon, PA — 37 mi23. Lock Haven, PA — 38 mi34. Lewistown, PA — 39 mi45. near Middletown, PA — 41 mi5
  1. Williamsport, PA 32 mi (51 km)
  2. Lebanon, PA 37 mi (60 km)
  3. Lock Haven, PA 38 mi (62 km)
  4. Lewistown, PA 39 mi (64 km)
  5. near Middletown, PA 41 mi (66 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: 40.7831, -76.8617.