Monthly weather forecast and climate
Mackinac Island, MI

Mackinac Island has a humid continental type of climate (Köppen climate classification Dfb) with warm, humid summers and cold, frosty winters. It lies in the eastern portion of Lake Huron in the Great Lakes region and is part of the American state of Michigan. Lake Huron moderates the climate of Mackinac Island and prevents extreme cold despite the island's location in the temperate latitudes.

Mackinac Island has an average elevation of 181 meters above sea level and lies in the Mackinac Straits, between the Upper and Lower Peninsulas of Michigan. The topography consists of steep hills, and limestone formations as a significant portion of the island come under the Mackinac Island State Park. The wide variety of terrain includes bogs, forests, marshes, fields along with a long coastline. Many types of wildflowers and trees abundantly grow in the forests of the island.

Summers tend to be warm and humid in Mackinac Island as the average high temperature touches 77°F (25°C) at the peak of July. High temperatures mostly stay below 95°F (35°C), while the nights tend to be mild. Winters are cold with the average low temperature at 7°F (-13.9°C) in January, and the nights mostly remain below freezing. Breezes from Lake Huron have a localized cooling effect on the lakefront neighborhoods, which results in the formation of dense fog on the island during the winter. Spring and autumn are mild, with warm days and cold nights.

The sunshine lasts for an annual 2040 hours in Mackinac Island with 80 days of clear skies in the year. Yearly precipitation is to the tune of 32" (812.8mm) with 168 rainy days in the year. Rainfall is throughout the year, but late summer and autumn tend to be the wettest. Snowfall is an abundant 89" (2260.6mm) and lasts from October to April. Frost and fog are frequent in the winter. Mackinac Island has at least 19 days in the year when the night temperatures drop below 0°F (-17.8°C).
The best time to visit Mackinac Island is from late spring in May to early autumn in September. The temperatures are mostly above freezing, and the sunshine is moderate in the shoulder seasons. Spring is drier than autumn. Summers are warm and bright with a touch of humidity but generally comfortable weather. The peak tourist season during summer makes spring and autumn better as the crowds are fewer, and accommodations are cheaper.

The worst time to visit Mackinac Island is at the peak of winter from December to February. The snowfall is massive, and the island remains generally closed for visitors. Snowpack assumes thick proportions, and the only motorized transport is in the form of snowmobiles. Winter temperatures may drop below 0°F (-17.8°C) during the night, while most of the days remain below freezing. Tourists usually avoid Mackinac Island in the icy winter conditions.

Mackinac Island is prone to thunderstorms during the summer and snowstorms during the winter. The ample rainfall, low elevation, and surrounding large water bodies create a risk of flooding during late spring with the thawing of ice. Late spring and summer are prone to thunderstorms with frequent lightning strikes. Snowstorms occur in the winter as a single day may record more than 10" (254mm) of snowfall.

The average temperatures are in the frigid zone of 7°F (-13.9°C) to 25°F (-3.9°C) as January gathers 20" (508mm) of snowfall. Weather in January »

February is the coldest and driest month of the year in Mackinac Island as the average low-temperature drops to 5°F (-15°C) with 1.5" (38.1mm) of rainfall. Weather in February »

The beginning of spring sees temperatures in the average range of 16°F (-8.9°C) to 36°F (2.2°C) with ample snowfall. Weather in March »

The days on Mackinac Island often cross 50°F (10°C), while the nights are cold and occasionally drop below freezing. Weather in April »

May is warm and bright at the peak of the spring season in Mackinac Island with comfortable temperatures in the average range of 39°F (3.9°C) to 63°F (17.2°C). Weather in May »

June in Mackinac Island receives 2.9" (73.7mm) of precipitation as the ground loses any remaining snow cover. Weather in June »

July is the hottest and sunniest month of the year in Mackinac Island as the temperatures cook up to an average of 77°F (25°C). Weather in July »

The average temperatures on Mackinac Island are in the beautiful 54°F (12.2°C) to 75°F (23.9°C) zone with a touch of humidity in the air. Weather in August »

The weather is usually mild as the temperatures average in the 46.9°F (8.3°C) to 66°F (18.9°C) range. Weather in September »

The average temperatures are in the 37°F (2.8°C) to 55°F (12.8°C) zone as a few nights drop below freezing on Mackinac Island. Weather in October »

The average temperatures are between 28°F (-2.2°C) and 41°F (5°C) with the majority of the nights below freezing. Weather in November »

The abundant snowfall covers the ground and forms a deep icepack as the average temperatures remain in the frigid 16°F (-8.9°C) to 30°F (-1.1°C) range. Weather in December »

What is the coldest month in Mackinac Island?

With an average high-temperature of 24.8°F (-4°C) and an average low-temperature of 6.8°F (-14°C), January is the coldest month in Mackinac Island.

How many days does it rain in Mackinac Island?

In Mackinac Island, during the entire year, the rain falls for 168 days and collects up to 31.3" (795mm) of precipitation.

What is the driest month in Mackinac Island?

February is the month with the least rainfall. Rain falls for 14 days and accumulates 1.5" (37mm) of precipitation.

What are the months with the coldest sea water in Mackinac Island?

February through April, with an average sea temperature of 35.6°F (2°C), are months with the coldest seawater in Mackinac Island. For swimming, this is considered life-threatening and very dangerous. The water feels painfully cold, and hyperventilation quickly occurs. A specialized swimsuit is mandatory to reduce thermal damage.

What is the warmest month in Mackinac Island?

July is the warmest month in Mackinac Island, with an average high-temperature of 77°F (25°C) and an average low-temperature of 53.6°F (12°C).

What is the month with the warmest sea water in Mackinac Island?

With an average sea temperature of 60.8°F (16°C), August is the month with the warmest seawater in Mackinac Island, Michigan. For most, swimming in 60.8°F (16°C) is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 69.8°F (21°C) to 59°F (15°C).

What is the wettest month in Mackinac Island?

September is the month with the most rainfall in Mackinac Island, Michigan. Rain falls for 13 days and accumulates 3.9" (99mm) of precipitation.
Average rainfall - Mackinac Island, MI
Average rainfall days - Mackinac Island, MI
Average sea temperature - Mackinac Island, MI
Average daylight / Average sunshine - Mackinac Island, MI
Average UV index - Mackinac Island, MI