Mackinac Island, MI climate
Mackinac Island has cold, snowy winters and cool summers. A typical July afternoon reaches 75°, a January night drops to 13°, and about 88 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Mackinac Island feels like
Winter
Spring
Summer
Fall
Mackinac Island weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 26° | 13° | 1.7" | 24.2" | 16 | 29 | 6° – 28° |
| February | 28° | 12° | 1.2" | 18.1" | 12 | 27 | 5° – 30° |
| March | 37° | 20° | 1.7" | 11.6" | 10 | 21 | 18° – 41° |
| April | 48° | 30° | 2.6" | 4.9" | 12 | 4 | 31° – 46° |
| May | 61° | 41° | 2.9" | 0.1" | 12 | 0 | 45° – 57° |
| June | 70° | 51° | 3.0" | 0 | 11 | 0 | 57° – 66° |
| July | 75° | 58° | 3.0" | 0 | 11 | 0 | 60° – 70° |
| August | 75° | 58° | 3.1" | 0 | 10 | 0 | 62° – 70° |
| September | 68° | 51° | 3.5" | 0 | 13 | 0 | 54° – 64° |
| October | 55° | 40° | 4.1" | 0.5" | 16 | 0 | 43° – 54° |
| November | 42° | 31° | 2.6" | 6.2" | 15 | 6 | 30° – 43° |
| December | 32° | 21° | 2.1" | 22.0" | 15 | 20 | 18° – 36° |
| Year | 51° | 35° | 31.5" | 87.6" | 153 | 107 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Mackinac Island
Mackinac Island gets 32 inches of rain and melted snow a year. October is the wettest month and February the driest. Rain or snow falls on about 153 days a year. Snow covers the ground about 107 days of the year.
About 167 frost-free days a year
In half of years the last 32° night comes by May 7 and the first one by October 23. That leaves about 167 frost-free days for gardens, shorter than 64% of U.S. towns.
Heating and cooling a home in Mackinac Island
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Mackinac Island, 97% of that work is heating and 3% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
Mackinac Island and its neighbors
Mackinac Island borders 2 towns with climate data. January nights across them vary by 2.1°. St. Ignace has the coldest January nights (11°) and Bois Blanc the hottest July afternoons (76°). Mackinac Island’s January low is 13° and its July high 75°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Mackinac Island compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Mackinac Island averaged 1.9° warmer than the 1900s. The biggest change is in February (+3.5°). The shift is larger than in 92% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Mackinac Island’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 5° to 30°. August is the most reliable, staying within 8°.
Common questions about Mackinac Island’s climate
What is the coldest month in Mackinac Island?
February, with a typical high of 28° and a low of 12°.
What is the hottest month in Mackinac Island?
July, with a typical high of 75° and a low of 58°.
How much snow does Mackinac Island get?
About 88 inches in a normal winter, most of it in January.
When is the first frost in Mackinac Island?
In half of years the first 32° night comes by October 23, and the last spring frost by May 7.
What is the rainiest month in Mackinac Island?
October, with 4.1 inches of rain and melted snow. The year totals 32 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Mackinac Island itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Cheboygan, MI (16 mi, snow) and St Ignace Mackinac Br, MI (5 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.