U.S. Frost Dates by Weather Station

NOAA station USW00014739 · Massachusetts

Frost Dates near Boston, MA

NOAA weather station Boston Logan International Airport (USW00014739), Massachusetts · elevation 12 ft (4 m) · hardiness zone 7a*

Boston is the nearest town to the station (2.5 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter April 17only 1 spring in 10 still has a frost later
  • Typical last frostApril 450% chance of a frost after it
  • Typical first fall frostNovember 950% chance of a frost before it
  • Frost-free season218 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season near Boston, MASpring: a frost after March 25 in 9 years out of 10, after April 4 in half of the years, after April 17 in 1 year out of 10. Fall: the first frost comes before October 29 in 1 year out of 10, before November 9 in half of the years, before November 22 in 9 years out of 10. Typical frost-free season: 218 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 4First frost ~Nov 9Frost season near Boston, MASpring: a frost after March 25 in 9 years out of 10, after April 4 in half of the years, after April 17 in 1 year out of 10. Fall: the first frost comes before October 29 in 1 year out of 10, before November 9 in half of the years, before November 22 in 9 years out of 10. Typical frost-free season: 218 days.JFMAMJJASONDLast frost ~Apr 4First frost ~Nov 9
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)April 17October 29
50% (typical)April 4November 9
90% (likely)March 25November 22
Frost-free season (32°F, 50% chance)
218 days
Hard frost (28°F), last in spring, 50% chance after
March 28
Hard frost (28°F), first in fall, 50% chance before
November 21

The last 15 years (2006–2020 normals)

Typical last frost April 4 (same as the 30-year normal), typical first fall frost November 10 (1 day later). Frost-free season 220 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 near Boston: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 17, 20% April 11, 30% April 8, 40% April 6, 50% April 4, 60% April 3, 70% April 1, 80% March 30, 90% March 25. Observed last spring frost in recent years: 2021 April 3, 2022 March 30, 2023 April 3, 2024 March 24, 2025 April 9, 2026 April 9.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 17Apr 4Mar 252021: April 32022: March 302023: April 32024: March 242025: April 92026: April 9Fall near Boston: chance of a frost before this dateFall, chance of a frost before the date: 10% October 29, 20% November 1, 30% November 3, 40% November 6, 50% November 9, 60% November 12, 70% November 14, 80% November 17, 90% November 22. Observed first fall frost in recent years: 2021 November 23, 2022 November 18, 2023 November 12, 2024 November 13, 2025 November 20.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Oct 29Nov 9Nov 222021: November 232022: November 182023: November 122024: November 132025: November 20
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 3November 23
2022March 30November 18
2023April 3November 12
2024March 24November 13
2025April 9November 20
2026April 9season not over yet

What these dates mean

Setting out tender crops on the early spring date of March 25 carries a 90% chance of a frost later, making it a gamble for Boston gardeners. The cautious alternative is April 17, when only a 10% chance remains that a light frost will still occur, providing a much lower risk for those delicate seedlings.

For the autumn season, the cautious date to finish harvesting tender crops is October 29, where there is just a 10% chance a light frost has already arrived; waiting until November 22 would be a gamble with a 90% chance of frost earlier. The 50% date for light frost in spring is April 4 and in fall is November 9, each marking an even chance of frost. The median hard-frost dates are March 28 and November 21; hard frosts matter more because the lower 28 °F temperature can damage plants that survive a light frost.

How to read the probabilities

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

  • Spring: "10% after April 17" 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 29" 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 Boston, MANumbered nearest stations: 1 — Jamaica Plain, MA — 7 mi; 2 — Hingham, MA — 11 mi; 3 — Blue Hill Coop, MA — 12 mi; 4 — Marblehead, MA — 12 mi; 5 — Reading, MA — 13 mi.MANHCTRIVT25 mi · 40 km1. Jamaica Plain, MA — 7 mi12. Hingham, MA — 11 mi23. Blue Hill Coop, MA — 12 mi34. Marblehead, MA — 12 mi45. Reading, MA — 13 mi5
  1. Jamaica Plain, MA 7 mi (11 km)
  2. Hingham, MA 11 mi (17 km)
  3. Blue Hill Coop, MA 12 mi (19 km)
  4. Marblehead, MA 12 mi (20 km)
  5. Reading, MA 13 mi (20 km)

Sources

* Hardiness zone 7a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 42.3606, -71.0106.