Photo: Public domain · Public domainFew U.S. towns have cooler summers than Isle au Haut
January nights here settle around 15°. Only 60° separates winter nights from summer afternoons. By precipitation alone, it ranks wetter than 86% of U.S. towns. Picnics, hikes and garden evenings come into their own from June to September, with highs of 67–75°.
A year in Isle au Haut at a glance
Each month’s typical high and low, and what it brings.
What stands out about Isle au Haut’s climate
Compared with towns across the U.S., with Isle au Haut’s place in Maine beside it.
What a year in Isle au Haut feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 51 inches of rain a year
October is the wettest month and August the driest.
Rain + melted snow by month
Inches of water
Living with Isle au Haut’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 6a.
Months with highs of 62–84° and lows of 40° or more: June, July, August and September. 23 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Isle au Haut from natural hazards, coastal flooding is the largest share (38%); heat waves, cold waves, winter storms and ice storms together are 13%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Isle au Haut and its neighbors
Every town next door is within a degree of Isle au Haut in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Isle au Haut averaged 1.6° warmer than the 1900s. The biggest change is in December (+3.3°).
A bigger shift than in 68% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Isle au Haut compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Isle au Haut’s place among Maine’s.
Isle au Haut weather by month
Highs, lows and precipitation from NOAA’s grid at Isle au Haut’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 31° | 15° | 4.4" | 14° – 30° |
| February | 33° | 17° | 3.6" | 11° – 31° |
| March | 40° | 24° | 4.4" | 25° – 39° |
| April | 50° | 34° | 4.4" | 38° – 47° |
| May | 60° | 43° | 3.8" | 46° – 56° |
| June | 69° | 52° | 4.2" | 57° – 64° |
| July | 75° | 58° | 3.2" | 62° – 69° |
| August | 74° | 58° | 3.1" | 63° – 69° |
| September | 67° | 52° | 4.1" | 56° – 64° |
| October | 56° | 42° | 5.5" | 45° – 55° |
| November | 46° | 32° | 5.0" | 34° – 43° |
| December | 37° | 22° | 5.2" | 23° – 37° |
| Year | 53° | 37° | 50.9" |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 11° to 31°. August is the most reliable, staying within 6°.
Where Isle au Haut’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Isle au Haut’s center.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Isle au Haut’s climate
What is the weather like in Isle au Haut?
A typical July afternoon reaches 75°, a January night drops to 15°. Colder January nights than 84% of U.S. towns; cooler July afternoons than 98% of U.S. towns.
How cold does it get in Isle au Haut in winter?
January nights average 15°. In the coldest January of the last 30 years the month averaged 14°.
How hot does it get in Isle au Haut?
July, with a typical high of 75°. 90° days are rare.
What growing zone is Isle au Haut in?
Zone 6a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −5°.
What is the best time of year to visit Isle au Haut?
By one simple rule (highs of 62–84° and lows of 40° or more), June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Isle au Haut getting warmer?
Yes: 1991–2020 averaged 1.6° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 68% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Isle au Haut.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.