U.S. Frost Dates by Weather Station

NOAA station USC00175675 · Maine

Frost Dates for Newcastle, ME

NOAA weather station Newcastle (USC00175675), Maine · elevation 213 ft (65 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 10only 1 spring in 10 still has a frost later
  • Typical last frostApril 2750% chance of a frost after it
  • Typical first fall frostOctober 1850% chance of a frost before it
  • Frost-free season172 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Newcastle, MESpring: a frost after April 16 in 9 years out of 10, after April 27 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before October 3 in 1 year out of 10, before October 18 in half of the years, before November 2 in 9 years out of 10. Typical frost-free season: 172 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 27First frost ~Oct 18Frost season at Newcastle, MESpring: a frost after April 16 in 9 years out of 10, after April 27 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before October 3 in 1 year out of 10, before October 18 in half of the years, before November 2 in 9 years out of 10. Typical frost-free season: 172 days.JFMAMJJASONDLast frost ~Apr 27First 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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 10October 3
50% (typical)April 27October 18
90% (likely)April 16November 2
Frost-free season (32°F, 50% chance)
172 days
Hard frost (28°F), last in spring, 50% chance after
April 14
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 25 (2 days earlier than the 30-year normal), typical first fall frost October 22 (4 days later). Frost-free season 179 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 Newcastle: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 10, 20% May 5, 30% May 2, 40% April 30, 50% April 27, 60% April 25, 70% April 22, 80% April 20, 90% April 16. Observed last spring frost in recent years: 2021 April 22, 2022 April 21, 2023 May 18, 2024 April 27.Spring: last frostChance of a frost after this date10%50%90%May 1May 10Apr 27Apr 162021: April 222022: April 212023: May 182024: April 27Fall at Newcastle: chance of a frost before this dateFall, chance of a frost before the date: 10% October 3, 20% October 7, 30% October 10, 40% October 14, 50% October 18, 60% October 21, 70% October 25, 80% October 29, 90% November 2. Observed first fall frost in recent years: 2021 November 4, 2022 October 11, 2023 October 31, 2024 October 17, 2025 November 3.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 3Oct 18Nov 22021: November 42022: October 112023: October 312024: October 172025: November 3
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 22November 4
2022April 21October 11
2023May 18October 31
2024April 27October 17
2025incomplete recordNovember 3
2026incomplete recordseason not over yet

What these dates mean

October 3 is the cautious fall date to finish harvesting tender crops in Newcastle.

The 50% dates are April 27 for spring light frost and October 18 for fall light frost; they represent even odds of a frost occurring later (spring) or earlier (fall). The cautious spring date for setting out tender crops is May 10, and the cautious fall date is October 3. The 50% hard-frost dates are April 14 and November 1. Because hard frost can kill seedlings, its 50% dates are useful reference points for planning. The interval between the two 32°F 50% dates is 172 days, based on 30 years of record.

A hard frost at 28 °F is more damaging than a light frost at 32 °F because the lower temperature can freeze plant tissues that survive the milder 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 3" 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 Newcastle, MENumbered nearest stations: 1 — Tenants Harbor, ME — 16 mi; 2 — Gardiner, ME — 17 mi; 3 — West Rockport, ME — 22 mi; 4 — near Augusta, ME — 23 mi; 5 — near Waterville, ME — 34 mi.NH25 mi · 40 km1. Tenants Harbor, ME — 16 mi12. Gardiner, ME — 17 mi23. West Rockport, ME — 22 mi34. near Augusta, ME — 23 mi45. near Waterville, ME — 34 mi5
  1. Tenants Harbor, ME 16 mi (26 km)
  2. Gardiner, ME 17 mi (28 km)
  3. West Rockport, ME 22 mi (35 km)
  4. near Augusta, ME 23 mi (37 km)
  5. near Waterville, ME 34 mi (55 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: 44.0436, -69.5375.