U.S. Frost Dates by Weather Station

NOAA station USC00276818 · New Hampshire

Frost Dates for Pinkham Notch, NH

NOAA weather station Pinkham Notch (USC00276818), New Hampshire · elevation 2025 ft (617 m) · hardiness zone 5a*

  • Lower-risk planting dateafter June 1only 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 season135 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Pinkham Notch, NHSpring: a frost after May 3 in 9 years out of 10, after May 18 in half of the years, after June 1 in 1 year out of 10. Fall: the first frost comes before September 15 in 1 year out of 10, before October 1 in half of the years, before October 14 in 9 years out of 10. Typical frost-free season: 135 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 18First frost ~Oct 1Frost season at Pinkham Notch, NHSpring: a frost after May 3 in 9 years out of 10, after May 18 in half of the years, after June 1 in 1 year out of 10. Fall: the first frost comes before September 15 in 1 year out of 10, before October 1 in half of the years, before October 14 in 9 years out of 10. Typical frost-free season: 135 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.

Frost dates (32°F)

Probability of frost, based on 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)June 1September 15
50% (typical)May 18October 1
90% (likely)May 3October 14
Frost-free season (32°F, 50% chance)
135 days
Hard frost (28°F), last in spring, 50% chance after
May 4
Hard frost (28°F), first in fall, 50% chance before
October 12

The last 15 years (2006–2020 normals)

Typical last frost May 16 (2 days earlier than the 30-year normal), typical first fall frost October 3 (2 days later). Frost-free season 137 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 Pinkham Notch: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 1, 20% May 28, 30% May 24, 40% May 21, 50% May 18, 60% May 14, 70% May 11, 80% May 8, 90% May 3. Observed last spring frost in recent years: 2021 May 8, 2022 May 10, 2023 May 27, 2024 April 28, 2025 May 2.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 1May 18May 32021: May 82022: May 102023: May 272024: April 282025: May 2Fall at Pinkham Notch: chance of a frost before this dateFall, chance of a frost before the date: 10% September 15, 20% September 21, 30% September 25, 40% September 28, 50% October 1, 60% October 2, 70% October 5, 80% October 8, 90% October 14. Observed first fall frost in recent years: 2021 October 25, 2022 September 30, 2023 October 24, 2024 October 16, 2025 October 3.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Nov 1Sep 15Oct 1Oct 142021: October 252022: September 302023: October 242024: October 162025: October 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
2021May 8October 25
2022May 10September 30
2023May 27October 24
2024April 28October 16
2025May 2October 3
2026incomplete recordseason not over yet

What these dates mean

The cautious fall date in Pinkham Notch for finishing the harvest is September 15, which carries a 10 % chance that a light frost has arrived earlier. A light frost is a gamble on October 14, where there is a 90 % chance it has arrived earlier, while the 50 % date in fall is October 1, indicating an even chance of a light frost earlier than that date.

In spring, the cautious date for setting out tender crops is June 1, with only a 10 % chance of a light frost later, whereas planting on May 3 involves a 90 % chance of a light frost later. The 50 % spring date is May 18, marking an even chance of a light frost later than that date, and the 50 % hard-frost dates are May 4 and October 12.

A hard frost at 28 °F can freeze plant tissue that survives a light frost at 32 °F, making it more damaging.

How to read the probabilities

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

  • Spring: "10% after June 1" 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 15" 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 Pinkham Notch, NHNumbered nearest stations: 1 — Berlin, NH — 14 mi; 2 — North Conway, NH — 15 mi; 3 — York Pond, NH — 18 mi; 4 — Lancaster, NH — 23 mi; 5 — Bridgton, ME — 28 mi.MENHVT25 mi · 40 km1. Berlin, NH — 14 mi12. North Conway, NH — 15 mi23. York Pond, NH — 18 mi34. Lancaster, NH — 23 mi45. Bridgton, ME — 28 mi5
  1. Berlin, NH 14 mi (22 km)
  2. North Conway, NH 15 mi (25 km)
  3. York Pond, NH 18 mi (28 km)
  4. Lancaster, NH 23 mi (37 km)
  5. Bridgton, ME 28 mi (45 km)

Sources

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

Station coordinates: 44.2581, -71.2525.