U.S. Frost Dates by Weather Station

NOAA station USW00094746 · Massachusetts

Frost Dates for Worcester, MA

NOAA weather station Worcester Regional Airport (USW00094746), Massachusetts · elevation 1000 ft (305 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 5only 1 spring in 10 still has a frost later
  • Typical last frostApril 2350% chance of a frost after it
  • Typical first fall frostOctober 2150% chance of a frost before it
  • Frost-free season181 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Worcester, MASpring: a frost after April 11 in 9 years out of 10, after April 23 in half of the years, after May 5 in 1 year out of 10. Fall: the first frost comes before October 6 in 1 year out of 10, before October 21 in half of the years, before November 3 in 9 years out of 10. Typical frost-free season: 181 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 23First frost ~Oct 21Frost season at Worcester, MASpring: a frost after April 11 in 9 years out of 10, after April 23 in half of the years, after May 5 in 1 year out of 10. Fall: the first frost comes before October 6 in 1 year out of 10, before October 21 in half of the years, before November 3 in 9 years out of 10. Typical frost-free season: 181 days.JFMAMJJASONDLast frost ~Apr 23First frost ~Oct 21
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)May 5October 6
50% (typical)April 23October 21
90% (likely)April 11November 3
Frost-free season (32°F, 50% chance)
181 days
Hard frost (28°F), last in spring, 50% chance after
April 11
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 21 (2 days earlier than the 30-year normal), typical first fall frost October 24 (3 days later). Frost-free season 185 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 Worcester: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 5, 20% May 2, 30% April 29, 40% April 25, 50% April 23, 60% April 21, 70% April 18, 80% April 15, 90% April 11. Observed last spring frost in recent years: 2021 April 23, 2022 April 18, 2023 April 9, 2024 April 25, 2025 April 12, 2026 April 22.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 5Apr 23Apr 112021: April 232022: April 182023: April 92024: April 252025: April 122026: April 22Fall at Worcester: chance of a frost before this dateFall, chance of a frost before the date: 10% October 6, 20% October 10, 30% October 14, 40% October 18, 50% October 21, 60% October 24, 70% October 27, 80% October 30, 90% November 3. Observed first fall frost in recent years: 2021 November 4, 2022 November 9, 2023 November 1, 2024 November 10, 2025 November 2.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 6Oct 21Nov 32021: November 42022: November 92023: November 12024: November 102025: November 2
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 4
2022April 18November 9
2023April 9November 1
2024April 25November 10
2025April 12November 2
2026April 22season not over yet

What these dates mean

May 5 is the cautious spring date, with only a ten-percent chance of a light frost later, and it lets a gardener set out tender crops when risk is low. The equally cautious fall date is October 6, also a ten-percent chance of a light frost earlier, marking a safe point to finish harvesting tender crops.

The 50 percent dates are April 23 in spring and October 21 in fall; each indicates an even odds of a light frost occurring. The hard-frost 50 percent dates are April 11 for spring and November 1 for fall, marking when a 28 °F frost is as likely as not. Hard frost matters more than light frost because temperatures at 28 °F can damage plant tissue that usually survives a 32 °F 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 May 5" 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 6" 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 Worcester, MANumbered nearest stations: 1 — near Fiskdale, MA — 17 mi; 2 — North Foster, RI — 30 mi; 3 — Amherst, MA — 35 mi; 4 — Lowell, MA — 36 mi; 5 — Storrs, CT — 38 mi.CTNHNYVT25 mi · 40 km1. near Fiskdale, MA — 17 mi12. North Foster, RI — 30 mi23. Amherst, MA — 35 mi34. Lowell, MA — 36 mi45. Storrs, CT — 38 mi5
  1. near Fiskdale, MA 17 mi (27 km)
  2. North Foster, RI 30 mi (47 km)
  3. Amherst, MA 35 mi (56 km)
  4. Lowell, MA 36 mi (59 km)
  5. Storrs, CT 38 mi (60 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: 42.2706, -71.8731.