U.S. Frost Dates by Weather Station

NOAA station USC00172700 · Maine

Frost Dates for Eustis, ME

NOAA weather station Eustis (USC00172700), Maine · elevation 1260 ft (384 m) · hardiness zone 4b*

  • Lower-risk planting dateafter June 6only 1 spring in 10 still has a frost later
  • Typical last frostMay 2450% chance of a frost after it
  • Typical first fall frostSeptember 2150% chance of a frost before it
  • Frost-free season118 daystypical year, 32°F
  • Hardiness zone4bcalculated*

The year at a glance

Frost season at Eustis, MESpring: a frost after May 8 in 9 years out of 10, after May 24 in half of the years, after June 6 in 1 year out of 10. Fall: the first frost comes before September 6 in 1 year out of 10, before September 21 in half of the years, before October 4 in 9 years out of 10. Typical frost-free season: 118 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 24First frost ~Sep 21Frost season at Eustis, MESpring: a frost after May 8 in 9 years out of 10, after May 24 in half of the years, after June 6 in 1 year out of 10. Fall: the first frost comes before September 6 in 1 year out of 10, before September 21 in half of the years, before October 4 in 9 years out of 10. Typical frost-free season: 118 days.JFMAMJJASONDLast frost ~May 24First frost ~Sep 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)June 6September 6
50% (typical)May 24September 21
90% (likely)May 8October 4
Frost-free season (32°F, 50% chance)
118 days
Hard frost (28°F), last in spring, 50% chance after
May 10
Hard frost (28°F), first in fall, 50% chance before
October 2

The last 15 years (2006–2020 normals)

Typical last frost May 24 (same as the 30-year normal), typical first fall frost September 21. Frost-free season 119 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 Eustis: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 6, 20% June 3, 30% May 30, 40% May 27, 50% May 24, 60% May 21, 70% May 18, 80% May 14, 90% May 8.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 6May 24May 8Fall at Eustis: chance of a frost before this dateFall, chance of a frost before the date: 10% September 6, 20% September 10, 30% September 14, 40% September 17, 50% September 21, 60% September 24, 70% September 26, 80% September 30, 90% October 4.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 6Sep 21Oct 4
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

Setting out tender crops on the early spring date of May 8 in Eustis carries a 90 % chance that a light frost will still occur later that season, making it a gamble. The cautious spring date for tender crops is June 6, when only a 10 % chance of a later frost remains.

The 50 % date is May 24, indicating even odds for a light frost later in spring, while the 50 % date is September 21, indicating even odds for a light frost earlier in fall. For a cautious fall plan, the early date of September 6 is used, as it has a 10 % chance that a frost has already arrived; the late fall gamble falls on October 4 with a 90 % chance of an earlier frost.

A hard frost at 28 °F can injure plants that survive a 32 °F light frost, so the 50 % hard-frost dates of May 10 and October 2 are especially important.

How to read the probabilities

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

  • Spring: "10% after June 6" 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 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 Eustis, MENumbered nearest stations: 1 — Rangeley, ME — 19 mi; 2 — Jackman, ME — 31 mi; 3 — Farmington, ME — 39 mi; 4 — Madison, ME — 40 mi; 5 — First Connecticut Lake, NH — 41 mi.MENHVT25 mi · 40 km1. Rangeley, ME — 19 mi12. Jackman, ME — 31 mi23. Farmington, ME — 39 mi34. Madison, ME — 40 mi45. First Connecticut Lake, NH — 41 mi5
  1. Rangeley, ME 19 mi (30 km)
  2. Jackman, ME 31 mi (50 km)
  3. Farmington, ME 39 mi (63 km)
  4. Madison, ME 40 mi (65 km)
  5. First Connecticut Lake, NH 41 mi (66 km)

Sources

* Hardiness zone 4b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 45.2103, -70.4728.