U.S. Frost Dates by Weather Station

NOAA station USC00176881 · Maine

Frost Dates for Tenants Harbor, ME

NOAA weather station Tenants Harbor (USC00176881), Maine · elevation 21 ft (6 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 8only 1 spring in 10 still has a frost later
  • Typical last frostApril 2750% chance of a frost after it
  • Typical first fall frostOctober 2550% chance of a frost before it
  • Frost-free season178 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Tenants Harbor, MESpring: a frost after April 17 in 9 years out of 10, after April 27 in half of the years, after May 8 in 1 year out of 10. Fall: the first frost comes before October 10 in 1 year out of 10, before October 25 in half of the years, before November 6 in 9 years out of 10. Typical frost-free season: 178 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 27First frost ~Oct 25Frost season at Tenants Harbor, MESpring: a frost after April 17 in 9 years out of 10, after April 27 in half of the years, after May 8 in 1 year out of 10. Fall: the first frost comes before October 10 in 1 year out of 10, before October 25 in half of the years, before November 6 in 9 years out of 10. Typical frost-free season: 178 days.JFMAMJJASONDLast frost ~Apr 27First frost ~Oct 25
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 8October 10
50% (typical)April 27October 25
90% (likely)April 17November 6
Frost-free season (32°F, 50% chance)
178 days
Hard frost (28°F), last in spring, 50% chance after
April 14
Hard frost (28°F), first in fall, 50% chance before
November 6

The last 15 years (2006–2020 normals)

Typical last frost April 25 (2 days earlier than the 30-year normal), typical first fall frost October 28 (3 days later). Frost-free season 183 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 Tenants Harbor: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 8, 20% May 3, 30% May 1, 40% April 29, 50% April 27, 60% April 25, 70% April 23, 80% April 20, 90% April 17.Spring: last frostChance of a frost after this date10%50%90%May 1May 8Apr 27Apr 17Fall at Tenants Harbor: chance of a frost before this dateFall, chance of a frost before the date: 10% October 10, 20% October 16, 30% October 19, 40% October 22, 50% October 25, 60% October 28, 70% October 31, 80% November 2, 90% November 6.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 10Oct 25Nov 6
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.

What these dates mean

May 8 is the cautious spring date for light frost (32 °F) at Tenants Harbor, giving a gardener a 10 % chance that a frost will occur later and thus allowing tender crops to be set out with low risk. The parallel cautious fall date is October 10, when there is only a 10 % chance that a frost has arrived earlier, so tender crops can be finished harvesting with minimal chance of frost damage.

The 50% date in spring is April 27; it marks the point where a frost is equally likely to happen later or not. In fall the 50% date is October 25, indicating an even chance of a frost occurring earlier. The 50% hard-frost dates are April 14 in spring and November 6 in fall. Hard frost at 28 °F can injure or kill plants that survive a light frost at 32 °F, making it the more critical temperature threshold for tender crops.

How to read the probabilities

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

  • Spring: "10% after May 8" 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 10" 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 Tenants Harbor, MENumbered nearest stations: 1 — West Rockport, ME — 14 mi; 2 — Newcastle, ME — 16 mi; 3 — Belfast, ME — 30 mi; 4 — Gardiner, ME — 32 mi; 5 — near Augusta, ME — 37 mi.ME25 mi · 40 km1. West Rockport, ME — 14 mi12. Newcastle, ME — 16 mi23. Belfast, ME — 30 mi34. Gardiner, ME — 32 mi45. near Augusta, ME — 37 mi5
  1. West Rockport, ME 14 mi (23 km)
  2. Newcastle, ME 16 mi (26 km)
  3. Belfast, ME 30 mi (48 km)
  4. Gardiner, ME 32 mi (52 km)
  5. near Augusta, ME 37 mi (59 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: 43.9919, -69.2167.