U.S. Frost Dates by Weather Station

NOAA station USC00194313 · Massachusetts

Frost Dates for Lowell, MA

NOAA weather station Lowell (USC00194313), Massachusetts · elevation 110 ft (34 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 10only 1 spring in 10 still has a frost later
  • Typical last frostApril 3050% chance of a frost after it
  • Typical first fall frostOctober 1050% chance of a frost before it
  • Frost-free season164 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Lowell, MASpring: a frost after April 19 in 9 years out of 10, after April 30 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before September 30 in 1 year out of 10, before October 10 in half of the years, before October 24 in 9 years out of 10. Typical frost-free season: 164 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 30First frost ~Oct 10Frost season at Lowell, MASpring: a frost after April 19 in 9 years out of 10, after April 30 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before September 30 in 1 year out of 10, before October 10 in half of the years, before October 24 in 9 years out of 10. Typical frost-free season: 164 days.JFMAMJJASONDLast frost ~Apr 30First frost ~Oct 10
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 10September 30
50% (typical)April 30October 10
90% (likely)April 19October 24
Frost-free season (32°F, 50% chance)
164 days
Hard frost (28°F), last in spring, 50% chance after
April 18
Hard frost (28°F), first in fall, 50% chance before
October 22

The last 15 years (2006–2020 normals)

Typical last frost April 27 (3 days earlier than the 30-year normal), typical first fall frost October 17 (7 days later). Frost-free season 171 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 Lowell: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 10, 20% May 6, 30% May 3, 40% May 1, 50% April 30, 60% April 27, 70% April 25, 80% April 23, 90% April 19. Observed last spring frost in recent years: 2021 April 23, 2023 May 18, 2024 April 27, 2025 April 19.Spring: last frostChance of a frost after this date10%50%90%May 1May 10Apr 30Apr 192021: April 232023: May 182024: April 272025: April 19Fall at Lowell: chance of a frost before this dateFall, chance of a frost before the date: 10% September 30, 20% October 3, 30% October 5, 40% October 8, 50% October 10, 60% October 13, 70% October 15, 80% October 19, 90% October 24. Observed first fall frost in recent years: 2021 November 4, 2022 October 22, 2024 October 17, 2025 October 11.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 30Oct 10Oct 242021: November 42022: October 222024: October 172025: October 11
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
2022incomplete recordOctober 22
2023May 18incomplete record
2024April 27October 17
2025April 19October 11
2026incomplete recordseason not over yet

What these dates mean

Setting out tender crops on the early spring date, April 19, carries a 90% chance of a frost and is therefore a gamble for a Lowell gardener.

The cautious spring date is May 10, when only a 10% chance of frost remains, and the cautious fall date is September 30, also with a 10% chance of frost. The 50% dates—April 30 for spring and October 10 for fall—represent the point at which the odds of a light frost are even. The median hard-frost dates are April 18 and October 22, marking when a 28°F event becomes a 50-50 prospect.

A hard frost at 28°F matters more than a light frost at 32°F because it can damage or kill plants that would survive the milder temperature. Such damage can end a planting cycle early.

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 September 30" 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 Lowell, MANumbered nearest stations: 1 — Lawrence, MA — 11 mi; 2 — Nashua, NH — 12 mi; 3 — Reading, MA — 15 mi; 4 — Haverhill, MA — 17 mi; 5 — Middleton, MA — 18 mi.MANHVTME25 mi · 40 km1. Lawrence, MA — 11 mi12. Nashua, NH — 12 mi23. Reading, MA — 15 mi34. Haverhill, MA — 17 mi45. Middleton, MA — 18 mi5
  1. Lawrence, MA 11 mi (17 km)
  2. Nashua, NH 12 mi (19 km)
  3. Reading, MA 15 mi (23 km)
  4. Haverhill, MA 17 mi (28 km)
  5. Middleton, MA 18 mi (29 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: 42.6408, -71.3636.