Mackinac Island in Summer
In summer (June, July and August), Mackinac Island sees average daytime highs around 72°F and overnight lows near 60°F, with 9.8 in of rain over about 31 wet days across the season. It is the warmest season of the year and the 2nd-wettest season.
Over the season highs climb from about 63°F in early June to 71°F by late August. The sky is clear or mostly clear about 38% of the time across summer, and the air most often feels dry.
Summer is Mackinac Island's best season of the year to visit on our travel score. For the whole year in context, see Mackinac Island's year-round climate.
- Avg daytime high
- 72°F
- warmest season of the year
- Avg overnight low
- 60°F
- Rainfall
- 9.8 in
- 31 wet days
- Avg wind
- 9 mph
- Travel score
- 6.7
- best season of the year
- Months
- Jun · Jul · Aug
Temperature in Mackinac Island in Summer
Over the season highs climb from about 63°F in early June to 71°F by late August.
A typical summer day in Mackinac Island reaches about 72°F and drops to 60°F overnight. The warmest of the three months is July, the coolest June.
How summer really feels in Mackinac Island
Once humidity and wind are folded in, summer brings about 0 days that feel above 90°F and 0 that feel at or below 32°F.
summer sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.
Mackinac Island weather by month
How the three summer months (June, July and August) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 24° / 14° | 1.9 | 9.9 | 10.9 | 8.9 | 0.0 |
| Feb | 24° / 13° | 1.6 | 7.4 | 7.3 | 10.1 | 0.0 |
| Mar | 33° / 21° | 2.0 | 8.4 | 6.1 | 11.6 | 0.0 |
| Apr | 44° / 32° | 2.9 | 9.7 | 3.2 | 13.3 | 0.9 |
| May | 56° / 43° | 2.9 | 10.2 | 0.3 | 14.7 | 3.7 |
| Jun | 68° / 55° | 3.0 | 10 | 0 | 15.5 | 6.3 |
| Jul | 74° / 62° | 3.3 | 10.9 | 0 | 15.2 | 6.9 |
| Aug | 73° / 62° | 3.4 | 10 | 0 | 13.9 | 6.9 |
| Sep | 66° / 55° | 3.5 | 11.4 | 0 | 12.3 | 5.9 |
| Oct | 54° / 44° | 3.7 | 13.5 | 0.2 | 10.7 | 3.0 |
| Nov | 42° / 34° | 2.6 | 11.6 | 5.7 | 9.3 | 0.5 |
| Dec | 32° / 24° | 2.3 | 11.3 | 11.3 | 8.5 | 0.0 |
Cloud cover in Summer
The sky is clear or mostly clear about 38% of the time across summer.
Chance of precipitation in Summer
Mackinac Island gets around 9.8 in of rain over 31 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 9 mph across summer.
Sunrise & sunset in Summer
Daylight runs from about 15 h 18 min in early June to 13 h 12 min by late August. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 6.2 kWh/m².
Is summer a good time to visit Mackinac Island?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a reasonable time to visit Mackinac Island for sightseeing.
What to pack for Mackinac Island in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Mackinac Island sees daytime highs around 72°F and nights near 60°F. Pack sun protection. Worth having: light clothes and rain gear. About 31 days see rain.
Sea temperature near Mackinac Island in Summer
The nearest coast averages about 60°F across summer — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea offshore is warmest in August at about 66°F and coldest in February near 34°F.
The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 35 | 34 | 34 | 36 | 41 | 52 | 62 | 66 | 61 | 53 | 44 | 38 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Cool | Cool | Bracing | Bracing | Bracing |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 35 | Bracing |
| Feb | 34 | Bracing |
| Mar | 34 | Bracing |
| Apr | 36 | Bracing |
| May | 41 | Bracing |
| Jun | 52 | Bracing |
| Jul | 62 | Cool |
| Aug | 66 | Cool |
| Sep | 61 | Cool |
| Oct | 53 | Bracing |
| Nov | 44 | Bracing |
| Dec | 38 | Bracing |
UV index in Mackinac Island in Summer
Clear-sky midday UV across summer averages around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Mackinac Island peaks around June 19 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 7 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 1 | 2 | 3 | 5 | 7 | 8 | 8 | 7 | 5 | 3 | 2 | 1 |
| Level | Low | Low | Moderate | Moderate | High | Very high | Very high | High | Moderate | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 2 | Low |
| Mar | 3 | Moderate |
| Apr | 5 | Moderate |
| May | 7 | High |
| Jun | 8 | Very high |
| Jul | 8 | Very high |
| Aug | 7 | High |
| Sep | 5 | Moderate |
| Oct | 3 | Moderate |
| Nov | 2 | Low |
| Dec | 1 | Low |
Where is Mackinac Island?
Mackinac Island sits at 45.8°N, 84.6°W, 0 ft above sea level, in United States. The nearest listed city is Sault Ste. Marie, 47 mi away.
Topography around Mackinac Island
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Mackinac Island.
Within 2 miles, the terrain around Mackinac Island has only modest variations in elevation — a maximum elevation change of 351 ft around an average of 614 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 351 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,037 ft.
The land around Mackinac Island is covered by water (72%) and trees (24%) within 2 miles, water (75%) and trees (22%) within 10 miles, and trees (48%) and water (44%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Mackinac Island (45.8492°, -84.6189°, elevation 0 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.