Photo: Unknown photographer · Public domainDeer Isle’s winters are colder and snowier than most of the U.S.
A typical July afternoon reaches 76°, a January night drops to 13°, and about 69 inches of snow falls in a normal winter.
A year in Deer Isle at a glance
Each month’s typical high and low, and what it brings.
What stands out about Deer Isle’s climate
Compared with towns across the U.S., with Deer Isle’s place in Maine beside it.
What a year in Deer Isle feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 151 frost-free days a year
In half of years the last 32° night comes by May 7 and the first by October 5. Frost and day counts come from NOAA’s station at Belfast, ME, 15 miles from the town’s center, at about the same height.
The 2023 USDA map puts Deer Isle’s center in zone 6a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −7°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 69 inches of snow a winter
Snow, measured at W Rockport 1 Nnw, ME, falls mostly in February. Precipitation (rain plus melted snow) adds up to 49 inches a year; October is the wettest month and August the driest. Rain or snow falls on about 124 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Deer Isle
97% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Belfast, ME.
Living with Deer Isle’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
151 frost-free days in zone 6a. The last frost comes by May 7 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 5.
Months with highs of 62–84° and lows of 40° or more: June, July, August and September. 21 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Deer Isle from natural hazards, hurricanes are the largest share (27%); heat waves, cold waves, winter storms and ice storms together are 22%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Deer Isle and its neighbors
Sedgwick has the coldest January nights next door (12°, 1° colder) and Sedgwick the hottest July afternoons (78°, 2° warmer). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Deer Isle’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Deer Isle, ME | 13° | 76° | 49" | 69" |
| Corinth, NY | 9° | 77° | 51" | 60" |
| Gardner, MA | 14° | 80° | 49" | 75" |
| New Ipswich, NH | 14° | 80° | 50" | 75" |
| Hazleton, PA | 16° | 78° | 51" | 42" |
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 Deer Isle averaged 1.7° warmer than the 1900s. The biggest change is in December (+3.5°).
A bigger shift than in 70% 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 Deer Isle compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Deer Isle’s place among Maine’s.
Deer Isle weather by month
Highs, lows and precipitation from NOAA’s grid at Deer Isle’s center; snow, wet days and snow on the ground from W Rockport 1 Nnw, ME. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 30° | 13° | 4.2" | 17.2" | 10 | 13° – 29° |
| February | 32° | 15° | 3.4" | 19.2" | 9 | 9° – 30° |
| March | 39° | 23° | 4.2" | 11.3" | 10 | 24° – 38° |
| April | 51° | 33° | 4.3" | 3.5" | 11 | 38° – 47° |
| May | 61° | 43° | 3.8" | 0.0" | 12 | 47° – 56° |
| June | 70° | 52° | 4.2" | 0.0" | 12 | 58° – 65° |
| July | 76° | 58° | 3.2" | 0.0" | 11 | 63° – 70° |
| August | 75° | 58° | 3.1" | 0.0" | 9 | 64° – 70° |
| September | 68° | 51° | 4.0" | 0.0" | 9 | 56° – 64° |
| October | 56° | 41° | 5.4" | 0.2" | 11 | 44° – 55° |
| November | 45° | 31° | 4.8" | 2.3" | 10 | 34° – 43° |
| December | 36° | 21° | 4.9" | 15.0" | 12 | 22° – 35° |
| Year | 53° | 37° | 49.3" | 68.7" | 124 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 9° to 30°. August is the most reliable, staying within 6°.
Where Deer Isle’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 Deer Isle’s center.
- Snow: W Rockport 1 Nnw, ME.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Belfast, ME, 15 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- 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 Deer Isle’s climate
What is the weather like in Deer Isle?
A typical July afternoon reaches 76°, a January night drops to 13°, and about 69 inches of snow falls in a normal winter. Colder January nights than 89% of U.S. towns; cooler July afternoons than 98% of U.S. towns.
How cold does it get in Deer Isle in winter?
January nights average 13°. About 162 nights a year reach 32° or below and 15 reach 0° or below. In the coldest January of the last 30 years the month averaged 13°.
How much snow does Deer Isle get?
About 69 inches in a normal winter at W Rockport 1 Nnw, ME, most of it in February.
How hot does it get in Deer Isle?
July, with a typical high of 76° and a low of 58°. About 2 days a year reach 90° (Belfast, ME).
When is the first and last frost in Deer Isle?
In half of years the last spring frost (32°) comes by May 7 and the first fall frost by October 5, about 151 frost-free days, at Belfast, ME.
What growing zone is Deer Isle in?
Zone 6a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −7°.
What is the best time of year to visit Deer Isle?
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 Deer Isle getting warmer?
Yes: 1991–2020 averaged 1.7° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 70% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Deer Isle.
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.