U.S. Frost Dates by Weather Station

NOAA station USC00273626 · New Hampshire

Frost Dates for Greenland, NH

NOAA weather station Greenland (USC00273626), New Hampshire · elevation 95 ft (29 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 18only 1 spring in 10 still has a frost later
  • Typical last frostMay 450% chance of a frost after it
  • Typical first fall frostOctober 850% chance of a frost before it
  • Frost-free season157 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Greenland, NHSpring: a frost after April 23 in 9 years out of 10, after May 4 in half of the years, after May 18 in 1 year out of 10. Fall: the first frost comes before September 27 in 1 year out of 10, before October 8 in half of the years, before October 24 in 9 years out of 10. Typical frost-free season: 157 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 4First frost ~Oct 8Frost season at Greenland, NHSpring: a frost after April 23 in 9 years out of 10, after May 4 in half of the years, after May 18 in 1 year out of 10. Fall: the first frost comes before September 27 in 1 year out of 10, before October 8 in half of the years, before October 24 in 9 years out of 10. Typical frost-free season: 157 days.JFMAMJJASONDLast frost ~May 4First frost ~Oct 8
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 27 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 18September 27
50% (typical)May 4October 8
90% (likely)April 23October 24
Frost-free season (32°F, 50% chance)
157 days
Hard frost (28°F), last in spring, 50% chance after
April 23
Hard frost (28°F), first in fall, 50% chance before
October 21

The last 15 years (2006–2020 normals)

Typical last frost April 30 (4 days earlier than the 30-year normal), typical first fall frost October 14 (6 days later). Frost-free season 166 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 Greenland: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 18, 20% May 14, 30% May 10, 40% May 7, 50% May 4, 60% May 2, 70% April 29, 80% April 27, 90% April 23. Observed last spring frost in recent years: 2021 April 23, 2022 April 21, 2023 May 18, 2024 April 27.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 18May 4Apr 232021: April 232022: April 212023: May 182024: April 27Fall at Greenland: chance of a frost before this dateFall, chance of a frost before the date: 10% September 27, 20% October 1, 30% October 4, 40% October 6, 50% October 8, 60% October 11, 70% October 14, 80% October 18, 90% October 24. Observed first fall frost in recent years: 2021 November 3, 2022 October 28, 2023 October 31, 2024 October 17, 2025 October 10.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 27Oct 8Oct 242021: November 32022: October 282023: October 312024: October 172025: October 10
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 23November 3
2022April 21October 28
2023May 18October 31
2024April 27October 17
2025incomplete recordOctober 10
2026incomplete recordseason not over yet

What these dates mean

September 27 is the cautious fall date in Greenland for finishing the harvest, marking a 10% chance that a light frost has already arrived.

For a gardener, the 50% date is May 4 for spring light frost and October 8 for fall light frost; each represents an even odds of frost occurring later (spring) or earlier (fall). The cautious spring date for setting out tender crops is May 18, which carries only a 10% chance of a later frost, while the gamble date of April 23 carries a 90% chance. In fall, the cautious date to complete tender-crop harvest is September 27, whereas the gamble date of October 24 carries a 90% chance of an earlier frost.

Hard frosts at 28°F, with median dates of April 23 in spring and October 21 in fall, pose a greater risk to plants because the lower temperature can cause damage that a 32°F light frost may not.

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 September 27" 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 Greenland, NHNumbered nearest stations: 1 — Durham, NH — 11 mi; 2 — Epping, NH — 13 mi; 3 — Haverhill, MA — 22 mi; 4 — Groveland, MA — 22 mi; 5 — Lawrence, MA — 28 mi.NHMAMEVT25 mi · 40 km1. Durham, NH — 11 mi12. Epping, NH — 13 mi23. Haverhill, MA — 22 mi34. Groveland, MA — 22 mi45. Lawrence, MA — 28 mi5
  1. Durham, NH 11 mi (17 km)
  2. Epping, NH 13 mi (21 km)
  3. Haverhill, MA 22 mi (35 km)
  4. Groveland, MA 22 mi (35 km)
  5. Lawrence, MA 28 mi (45 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: 43.0211, -70.8258.