
Michigan consists of two peninsulas surrounded primarily by four of theGreat Lakes and a variety of nearby islands. TheUpper Peninsula is bounded on the southwest byWisconsin, and theLower Peninsula is bounded on the south byIndiana andOhio. Both land masses are also separated from the Canadian province ofOntario by waterways of the Great Lakes, and from each other by theStraits of Mackinac. Because its land is largely surrounded by the Great Lakes, which flow into theSaint Lawrence River, Michigan is the only U.S. state whose streams and rivers are almost entirely within the Great Lakes-St. Lawrence watershed.
Michigan'sterritorial waters include roughly half each ofLake Superior,Lake Michigan, andLake Huron, and smaller areas ofLake St. Clair andLake Erie. It includes an estimated 11,000 inland lakes.[1] It encompasses 58,110 square miles (150,500 km2) of land, 38,575 square miles (99,910 km2) of Great Lakes waters, and 1,305 square miles (3,380 km2) of inland waters. Its territorial waters are second in area only to those ofAlaska.[2] At a total area of 97,990 square miles (253,800 km2) – including those territorial waters – Michigan is the largest state east of theMississippi River, and the eleventh largest state overall. More than half of the state's land area – 30,156 square miles (78,100 km2) – is stillforest.
The state lies roughly between 41° and 49° north latitude, and between 82° and 91° west longitude.


The heavily forested Upper Peninsula is relatively mountainous in the west. ThePorcupine Mountains, which are part of one of the oldest mountain chains in the world,[3] rise to an altitude of almost 2,000 feet (610 m) above sea level and form the watershed between the streams flowing into Lake Superior and Lake Michigan. The surface on either side of this range is rugged. The state's highest point, in theHuron Mountains northwest of Marquette, isMount Arvon at 1,979 feet (603 m). The peninsula is as large as Connecticut, Delaware, Massachusetts, and Rhode Island combined but has only about 300,000 inhabitants.
The geographic orientation of Michigan's peninsulas makes for a long distance between the ends of the state.Ironwood, in the far western Upper Peninsula, lies 630 highway miles (1,015 km) fromLambertville in the Lower Peninsula's southeastern corner. The geographic isolation of the Upper Peninsula from Michigan's political and population centers makes the U.P. culturally and economically distinct.


The Lower Peninsula, shaped like a mitten, is 277 miles (446 km) long from north to south and 195 miles (314 km) from east to west and occupies more than two-thirds of the state's land area. The surface of the peninsula is generally level, broken by conical hills and glacialmoraines usually not more than a few hundred feet tall. The highest point in the Lower Peninsula is eitherBriar Hill at 1,705 feet (520 m), or one of several points nearby in the vicinity ofCadillac. The lowest point is the surface of Lake Erie at 571 feet (174 m).
A feature of Michigan that gives it the distinct shape of a mitten isthe Thumb. This peninsula projects out into Lake Huron and theSaginaw Bay. The geography of the Thumb is mainly flat with a few rolling hills. TheLeelanau Peninsula lies in theNorthern Lower Michigan region.See AlsoMichigan Regions


The Great Lakes that form most of the water boundary of Michigan areLake Erie,Lake Huron,Lake Michigan, andLake Superior. Because of the historical importance of shipping on the lakes, Michigan has about 150lighthouses, more than any other state.[4] (seeLighthouses in the United States) The state is bounded on the south by the states ofOhio andIndiana, sharing land and water boundaries with both.
Michigan's northern boundaries are almost entirely water boundaries, from south to north, withIllinois andWisconsin in Lake Michigan; then a land boundary with Wisconsin and the Upper Peninsula, that is principally demarcated by theMenominee andMontreal Rivers; then water boundaries again, in Lake Superior, with Wisconsin andMinnesota to the west, capped around by the Canadian province ofOntario to the north and east.
The northern boundary then runs completely through Lake Superior, from the western boundary with Minnesota to a point north of and aroundIsle Royale, thence traveling southeastward through the lake in a reasonably straight line to the Sault Ste. Marie area. InSoutheastern Michigan there is a water boundary with Canada along the entire lengths of the St. Clair River, Lake St. Clair (including theFirst Nation reserve ofWalpole Island) and the Detroit River. The southeastern boundary ends in the western end of Lake Erie with a three-way convergence of Michigan, Ohio and Ontario.
With the exception of two tiny areas on its borders – one drained by theMississippi River by way of theWisconsin River in the Upper Peninsula, the other by way of theKankakee-Illinois River in the Lower Peninsula – the rivers and streams of Michigan drain entirely into the Great Lakes.
The larger islands of Michigan includeIsle Royale andGrand Island in Lake Superior;Neebish andSugar islands in theSt. Mary's River;Drummond Island,Les Cheneaux Islands,Mackinac Island,Bois Blanc Island, andCharity Island in Lake Huron;Beaver Island, theFox Islands,North Manitou Island, andSouth Manitou Island in Lake Michigan;Harsens Island in Lake St. Clair; andBelle Isle andGrosse Ile in theDetroit River.
Keweenaw Bay,Whitefish Bay, and theBig andLittle Bay de Noc are the principal bays of the Upper Peninsula. TheGrand andLittle Traverse,Thunder, andSaginaw bays are found on the Lower Peninsula. After Alaska, Michigan has the longest shoreline of any state[citation needed], 3,288 miles (5,292 km). An additional 1,056 miles (1,699 km) can be added if islands are included. This roughly equals the length of the Atlantic Coast from Maine to Florida.
The state has 11,037 inland lakes comprising 1,305 square miles (3,380 km2) of inland water. No point in Michigan is more than 6 miles (9.7 km) from an inland lake or more than 85 miles (137 km) from one of the Great Lakes.[5]
Thestate's numerous rivers are generally short and shallow, though several are navigable by recreational watercraft. The principal ones include theAu Sable,Thunder Bay,Cheboygan, andSaginaw, all of which flow into Lake Huron; theOntonagon, andTahquamenon, which flow into Lake Superior; and theSt. Joseph,Kalamazoo,Grand,Muskegon,Manistee, andEscanaba, which flow into Lake Michigan.

The state is home to threeNational Park Service preserves:Isle Royale National Park, located in Lake Superior, about 30 miles (48 km) southeast ofThunder Bay, Ontario;Pictured Rocks National Lakeshore, on the Lake Superior shore betweenMunising andGrand Marais; andSleeping Bear Dunes National Lakeshore, on the Lake Michigan shore between the villages ofFrankfort,Empire, andGlen Arbor.
Other nationalprotected areas in the state include:Keweenaw National Historical Park,Huron National Forest,Manistee National Forest,Hiawatha National Forest,Ottawa National Forest,Fumee Lake Natural Area, andFather Marquette National Memorial. The largest section of theNorth Country National Scenic Trail also passes through Michigan.
With 78state parks, 19 state recreation areas, and 6state forests, Michigan has the largest state park andstate forest system of any state. These parks and forests includeHolland State Park,Mackinac Island State Park,Au Sable State Forest, andMackinaw State Forest.

Michigan has ahumid continental climate, although there are two distinct regions. The southern third of the Lower Peninsula (south ofSaginaw Bay and from theGrand Rapids area southward) have a warmer climate (Köppen climate classificationDfa) with hot summers and cold winters. The northern two-thirds of the Lower Peninsula and the entire Upper Peninsula has a more severe climate (KöppenDfb), with warm, but shorter summers and longer, cold to very cold winters. Some parts of the state average high temperatures below freezing from December through February, and into early March in the far northern parts. During the winter through the middle of February parts of the state are frequently subjected to heavylake-effect snow. The state averages from 30–40 inches (76–102 centimetres) of precipitation annually. Snow cover tends to be intermittent in the southern part of the state, but persistent in northern Lower Michigan and especially in the Upper Peninsula.

The entire state averages 30 days of thunderstorm activity per year. These can be severe, especially in the southern part of the state. The state averages 17tornadoes per year, which are more common in the extreme southern portion of the state. Portions of the southern border have been nearly as vulnerable historically as parts ofTornado Alley. Farther north, in the Upper Peninsula, tornadoes are rare.[6]
| Climate data for Detroit (DTW), 1991–2020 normals,[a] extremes 1874–present[b] | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °F (°C) | 67 (19) | 73 (23) | 86 (30) | 89 (32) | 95 (35) | 104 (40) | 105 (41) | 104 (40) | 100 (38) | 92 (33) | 81 (27) | 69 (21) | 105 (41) |
| Mean maximum °F (°C) | 53.0 (11.7) | 55.3 (12.9) | 69.3 (20.7) | 79.6 (26.4) | 87.2 (30.7) | 92.6 (33.7) | 93.8 (34.3) | 92.1 (33.4) | 89.3 (31.8) | 80.6 (27.0) | 66.7 (19.3) | 56.1 (13.4) | 95.4 (35.2) |
| Mean daily maximum °F (°C) | 32.3 (0.2) | 35.2 (1.8) | 45.9 (7.7) | 58.7 (14.8) | 70.3 (21.3) | 79.7 (26.5) | 83.7 (28.7) | 81.4 (27.4) | 74.4 (23.6) | 62.0 (16.7) | 48.6 (9.2) | 37.2 (2.9) | 59.1 (15.1) |
| Daily mean °F (°C) | 25.8 (−3.4) | 28.0 (−2.2) | 37.2 (2.9) | 48.9 (9.4) | 60.3 (15.7) | 69.9 (21.1) | 74.1 (23.4) | 72.3 (22.4) | 64.9 (18.3) | 53.0 (11.7) | 41.2 (5.1) | 31.3 (−0.4) | 50.6 (10.3) |
| Mean daily minimum °F (°C) | 19.2 (−7.1) | 20.8 (−6.2) | 28.6 (−1.9) | 39.1 (3.9) | 50.2 (10.1) | 60.2 (15.7) | 64.4 (18.0) | 63.2 (17.3) | 55.5 (13.1) | 44.0 (6.7) | 33.9 (1.1) | 25.3 (−3.7) | 42.0 (5.6) |
| Mean minimum °F (°C) | 0.1 (−17.7) | 3.5 (−15.8) | 12.0 (−11.1) | 25.5 (−3.6) | 36.3 (2.4) | 47.3 (8.5) | 54.1 (12.3) | 53.4 (11.9) | 41.6 (5.3) | 31.0 (−0.6) | 19.8 (−6.8) | 8.8 (−12.9) | −3.7 (−19.8) |
| Record low °F (°C) | −21 (−29) | −20 (−29) | −4 (−20) | 8 (−13) | 25 (−4) | 36 (2) | 42 (6) | 38 (3) | 29 (−2) | 17 (−8) | 0 (−18) | −11 (−24) | −21 (−29) |
| Averageprecipitation inches (mm) | 2.23 (57) | 2.08 (53) | 2.43 (62) | 3.26 (83) | 3.72 (94) | 3.26 (83) | 3.51 (89) | 3.26 (83) | 3.22 (82) | 2.53 (64) | 2.57 (65) | 2.25 (57) | 34.32 (872) |
| Average snowfall inches (cm) | 14.0 (36) | 12.5 (32) | 6.2 (16) | 1.5 (3.8) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 1.9 (4.8) | 8.9 (23) | 45.0 (114) |
| Average extreme snow depth inches (cm) | 7.1 (18) | 6.6 (17) | 4.4 (11) | 0.8 (2.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 1.1 (2.8) | 4.3 (11) | 10.0 (25) |
| Average precipitation days(≥ 0.01 in) | 13.4 | 11.0 | 11.1 | 12.5 | 12.9 | 10.7 | 10.5 | 9.7 | 9.5 | 10.6 | 11.0 | 13.1 | 136.0 |
| Average snowy days(≥ 0.1 in) | 10.7 | 9.2 | 5.3 | 1.5 | 0.1 | 0.0 | 0.0 | 0.0 | 0.0 | 0.2 | 2.6 | 8.0 | 37.6 |
| Averagerelative humidity (%) | 74.7 | 72.5 | 70.0 | 66.0 | 65.3 | 67.3 | 68.5 | 71.5 | 73.4 | 71.6 | 74.6 | 76.7 | 71.0 |
| Averagedew point °F (°C) | 16.2 (−8.8) | 17.6 (−8.0) | 25.9 (−3.4) | 35.1 (1.7) | 45.7 (7.6) | 55.6 (13.1) | 60.4 (15.8) | 59.7 (15.4) | 53.2 (11.8) | 41.4 (5.2) | 32.4 (0.2) | 21.9 (−5.6) | 38.7 (3.7) |
| Mean monthlysunshine hours | 119.9 | 138.3 | 184.9 | 217.0 | 275.9 | 301.8 | 317.0 | 283.5 | 227.6 | 176.0 | 106.3 | 87.7 | 2,435.9 |
| Percentagepossible sunshine | 41 | 47 | 50 | 54 | 61 | 66 | 69 | 66 | 61 | 51 | 36 | 31 | 55 |
| Averageultraviolet index | 1.2 | 2.0 | 3.6 | 5.4 | 6.9 | 8.0 | 8.2 | 7.1 | 5.3 | 3.1 | 1.6 | 1.1 | 4.4 |
| Source 1:NOAA (relative humidity, dew point, and sun 1961–1990)[7][8][9] | |||||||||||||
| Source 2: UV Index Today (1995 to 2022)[10] | |||||||||||||
| Climate data for Grand Rapids, Michigan (Gerald Ford Int'l), 1991–2020 normals, extremes 1892–present[c] | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °F (°C) | 66 (19) | 73 (23) | 87 (31) | 90 (32) | 95 (35) | 102 (39) | 108 (42) | 102 (39) | 98 (37) | 89 (32) | 81 (27) | 69 (21) | 108 (42) |
| Mean maximum °F (°C) | 51.3 (10.7) | 51.9 (11.1) | 67.9 (19.9) | 79.2 (26.2) | 86.0 (30.0) | 91.8 (33.2) | 92.5 (33.6) | 91.1 (32.8) | 87.8 (31.0) | 78.8 (26.0) | 65.3 (18.5) | 54.4 (12.4) | 94.3 (34.6) |
| Mean daily maximum °F (°C) | 31.0 (−0.6) | 33.7 (0.9) | 44.5 (6.9) | 57.8 (14.3) | 69.8 (21.0) | 79.4 (26.3) | 83.1 (28.4) | 80.9 (27.2) | 73.9 (23.3) | 60.7 (15.9) | 47.2 (8.4) | 36.1 (2.3) | 58.2 (14.6) |
| Daily mean °F (°C) | 24.8 (−4.0) | 26.6 (−3.0) | 35.7 (2.1) | 47.6 (8.7) | 59.2 (15.1) | 68.9 (20.5) | 72.8 (22.7) | 71.1 (21.7) | 63.5 (17.5) | 51.5 (10.8) | 40.0 (4.4) | 30.4 (−0.9) | 49.3 (9.6) |
| Mean daily minimum °F (°C) | 18.6 (−7.4) | 19.5 (−6.9) | 26.9 (−2.8) | 37.3 (2.9) | 48.6 (9.2) | 58.3 (14.6) | 62.5 (16.9) | 61.2 (16.2) | 53.1 (11.7) | 42.2 (5.7) | 32.8 (0.4) | 24.7 (−4.1) | 40.5 (4.7) |
| Mean minimum °F (°C) | −2.8 (−19.3) | 0.0 (−17.8) | 7.5 (−13.6) | 22.9 (−5.1) | 33.4 (0.8) | 44.0 (6.7) | 51.0 (10.6) | 49.3 (9.6) | 38.6 (3.7) | 28.6 (−1.9) | 18.9 (−7.3) | 6.3 (−14.3) | −6.3 (−21.3) |
| Record low °F (°C) | −22 (−30) | −24 (−31) | −13 (−25) | 3 (−16) | 21 (−6) | 32 (0) | 41 (5) | 39 (4) | 27 (−3) | 18 (−8) | −10 (−23) | −18 (−28) | −24 (−31) |
| Averageprecipitation inches (mm) | 2.52 (64) | 2.12 (54) | 2.39 (61) | 3.99 (101) | 4.00 (102) | 3.94 (100) | 3.86 (98) | 3.55 (90) | 3.43 (87) | 4.02 (102) | 3.10 (79) | 2.48 (63) | 39.40 (1,001) |
| Average snowfall inches (cm) | 22.6 (57) | 17.2 (44) | 7.6 (19) | 2.0 (5.1) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.3 (0.76) | 7.1 (18) | 20.8 (53) | 77.6 (197) |
| Average extreme snow depth inches (cm) | 9.0 (23) | 8.8 (22) | 5.7 (14) | 1.0 (2.5) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.1 (0.25) | 2.5 (6.4) | 6.3 (16) | 12.1 (31) |
| Average precipitation days(≥ 0.01 in) | 16.8 | 13.1 | 11.8 | 12.8 | 12.5 | 10.7 | 10.0 | 9.9 | 10.2 | 12.5 | 12.9 | 15.5 | 148.7 |
| Average snowy days(≥ 0.1 in) | 14.9 | 11.2 | 5.9 | 2.1 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.4 | 4.5 | 11.9 | 50.9 |
| Averagerelative humidity (%) | 77.2 | 74.2 | 71.1 | 66.8 | 65.4 | 68.1 | 69.6 | 73.3 | 76.1 | 74.6 | 76.9 | 79.5 | 72.7 |
| Averagedew point °F (°C) | 16.3 (−8.7) | 16.9 (−8.4) | 24.8 (−4.0) | 34.5 (1.4) | 45.0 (7.2) | 55.0 (12.8) | 60.3 (15.7) | 59.4 (15.2) | 53.1 (11.7) | 41.2 (5.1) | 31.6 (−0.2) | 21.7 (−5.7) | 38.3 (3.5) |
| Mean monthlysunshine hours | 88.3 | 116.0 | 168.2 | 210.2 | 255.9 | 286.8 | 296.5 | 264.2 | 206.0 | 152.4 | 82.0 | 62.1 | 2,188.6 |
| Percentagepossible sunshine | 30 | 39 | 45 | 52 | 56 | 62 | 64 | 61 | 55 | 45 | 28 | 22 | 49 |
| Source:NOAA (relative humidity, dew point, and sun 1961–1990)[12][13][14] | |||||||||||||
| Climate data for Lansing, Michigan (Capital Region Int'l), 1991−2020 normals, extremes 1863−present[d] | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °F (°C) | 66 (19) | 73 (23) | 86 (30) | 88 (31) | 96 (36) | 99 (37) | 103 (39) | 102 (39) | 99 (37) | 90 (32) | 79 (26) | 70 (21) | 103 (39) |
| Mean maximum °F (°C) | 51.7 (10.9) | 52.6 (11.4) | 68.2 (20.1) | 78.2 (25.7) | 85.4 (29.7) | 91.4 (33.0) | 92.3 (33.5) | 91.3 (32.9) | 87.8 (31.0) | 79.1 (26.2) | 65.4 (18.6) | 54.4 (12.4) | 94.3 (34.6) |
| Mean daily maximum °F (°C) | 30.6 (−0.8) | 33.5 (0.8) | 44.4 (6.9) | 57.6 (14.2) | 69.4 (20.8) | 78.9 (26.1) | 82.8 (28.2) | 80.6 (27.0) | 73.6 (23.1) | 60.5 (15.8) | 47.0 (8.3) | 35.7 (2.1) | 57.9 (14.4) |
| Daily mean °F (°C) | 23.9 (−4.5) | 25.9 (−3.4) | 35.2 (1.8) | 47.0 (8.3) | 58.4 (14.7) | 68.0 (20.0) | 71.8 (22.1) | 70.0 (21.1) | 62.5 (16.9) | 50.8 (10.4) | 39.5 (4.2) | 29.5 (−1.4) | 48.5 (9.2) |
| Mean daily minimum °F (°C) | 17.2 (−8.2) | 18.3 (−7.6) | 26.0 (−3.3) | 36.4 (2.4) | 47.5 (8.6) | 57.1 (13.9) | 60.9 (16.1) | 59.5 (15.3) | 51.5 (10.8) | 41.2 (5.1) | 31.9 (−0.1) | 23.3 (−4.8) | 39.2 (4.0) |
| Mean minimum °F (°C) | −5.6 (−20.9) | −3.0 (−19.4) | 5.3 (−14.8) | 21.0 (−6.1) | 31.2 (−0.4) | 41.5 (5.3) | 47.5 (8.6) | 45.7 (7.6) | 36.0 (2.2) | 26.0 (−3.3) | 15.9 (−8.9) | 3.9 (−15.6) | −9.4 (−23.0) |
| Record low °F (°C) | −29 (−34) | −37 (−38) | −25 (−32) | −6 (−21) | 19 (−7) | 27 (−3) | 31 (−1) | 26 (−3) | 19 (−7) | 10 (−12) | −5 (−21) | −25 (−32) | −37 (−38) |
| Averageprecipitation inches (mm) | 2.06 (52) | 1.71 (43) | 2.13 (54) | 3.26 (83) | 3.66 (93) | 3.76 (96) | 2.94 (75) | 3.48 (88) | 2.81 (71) | 3.16 (80) | 2.46 (62) | 1.90 (48) | 33.33 (847) |
| Average snowfall inches (cm) | 14.3 (36) | 12.9 (33) | 5.9 (15) | 1.7 (4.3) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.2 (0.51) | 3.9 (9.9) | 11.3 (29) | 50.2 (128) |
| Average extreme snow depth inches (cm) | 8.0 (20) | 7.6 (19) | 5.0 (13) | 1.1 (2.8) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 2.5 (6.4) | 5.4 (14) | 10.3 (26) |
| Average precipitation days(≥ 0.01 in) | 13.9 | 10.7 | 10.9 | 12.5 | 12.5 | 10.5 | 9.1 | 10.1 | 10.1 | 11.6 | 12.3 | 13.5 | 137.7 |
| Average snowy days(≥ 0.1 in) | 11.9 | 10.0 | 4.8 | 1.9 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.2 | 3.9 | 9.4 | 42.1 |
| Averagerelative humidity (%) | 78.8 | 76.2 | 73.3 | 67.6 | 66.7 | 69.0 | 71.0 | 74.9 | 77.5 | 76.1 | 78.6 | 81.1 | 74.2 |
| Averagedew point °F (°C) | 16.0 (−8.9) | 16.9 (−8.4) | 25.3 (−3.7) | 34.5 (1.4) | 45.1 (7.3) | 55.2 (12.9) | 60.3 (15.7) | 59.5 (15.3) | 53.2 (11.8) | 41.5 (5.3) | 32.2 (0.1) | 21.7 (−5.7) | 38.4 (3.6) |
| Mean monthlysunshine hours | 118.2 | 140.1 | 187.6 | 218.7 | 278.6 | 296.2 | 318.5 | 278.1 | 217.6 | 163.8 | 92.4 | 82.1 | 2,391.9 |
| Percentagepossible sunshine | 40 | 47 | 51 | 54 | 61 | 65 | 69 | 65 | 58 | 48 | 32 | 29 | 54 |
| Source:NOAA (relative humidity, dew point and sun 1961−1990)[15][16][17] | |||||||||||||
| Climate data for Marquette, Michigan (1991–2020 normals, extremes 1857–present) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °F (°C) | 57 (14) | 69 (21) | 82 (28) | 91 (33) | 100 (38) | 101 (38) | 108 (42) | 102 (39) | 98 (37) | 89 (32) | 74 (23) | 60 (16) | 108 (42) |
| Mean maximum °F (°C) | 42.5 (5.8) | 46.5 (8.1) | 57.5 (14.2) | 71.8 (22.1) | 83.1 (28.4) | 88.2 (31.2) | 89.8 (32.1) | 89.3 (31.8) | 84.7 (29.3) | 75.1 (23.9) | 58.8 (14.9) | 46.0 (7.8) | 91.9 (33.3) |
| Mean daily maximum °F (°C) | 24.6 (−4.1) | 26.9 (−2.8) | 35.3 (1.8) | 45.8 (7.7) | 58.7 (14.8) | 67.9 (19.9) | 74.6 (23.7) | 74.3 (23.5) | 67.3 (19.6) | 53.9 (12.2) | 40.6 (4.8) | 30.2 (−1.0) | 50.0 (10.0) |
| Daily mean °F (°C) | 18.5 (−7.5) | 19.7 (−6.8) | 28.2 (−2.1) | 38.4 (3.6) | 49.8 (9.9) | 59.0 (15.0) | 66.2 (19.0) | 66.2 (19.0) | 59.4 (15.2) | 47.0 (8.3) | 34.5 (1.4) | 24.4 (−4.2) | 42.6 (5.9) |
| Mean daily minimum °F (°C) | 12.4 (−10.9) | 12.5 (−10.8) | 21.0 (−6.1) | 31.0 (−0.6) | 40.8 (4.9) | 50.1 (10.1) | 57.7 (14.3) | 58.1 (14.5) | 51.6 (10.9) | 40.0 (4.4) | 28.5 (−1.9) | 18.6 (−7.4) | 35.2 (1.8) |
| Mean minimum °F (°C) | −3.5 (−19.7) | −2.4 (−19.1) | 5.3 (−14.8) | 20.5 (−6.4) | 31.2 (−0.4) | 39.8 (4.3) | 48.7 (9.3) | 49.2 (9.6) | 39.8 (4.3) | 30.1 (−1.1) | 16.3 (−8.7) | 2.7 (−16.3) | −8 (−22) |
| Record low °F (°C) | −27 (−33) | −33 (−36) | −19 (−28) | 3 (−16) | 16 (−9) | 29 (−2) | 36 (2) | 33 (1) | 28 (−2) | 13 (−11) | −9 (−23) | −20 (−29) | −33 (−36) |
| Averageprecipitation inches (mm) | 1.86 (47) | 1.47 (37) | 1.59 (40) | 2.74 (70) | 2.90 (74) | 3.05 (77) | 3.11 (79) | 2.31 (59) | 3.34 (85) | 3.43 (87) | 2.42 (61) | 1.98 (50) | 30.20 (767) |
| Average snowfall inches (cm) | 25.1 (64) | 20.9 (53) | 14.2 (36) | 8.4 (21) | 0.3 (0.76) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.9 (2.3) | 11.1 (28) | 21.1 (54) | 102.0 (259) |
| Average extreme snow depth inches (cm) | 25.2 (64) | 31.7 (81) | 32.6 (83) | 19.3 (49) | 1.5 (3.8) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 2.5 (6.4) | 9.1 (23) | 17.9 (45) | 36.1 (92) |
| Average precipitation days(≥ 0.01 in) | 17.7 | 12.2 | 10.8 | 10.4 | 11.8 | 11.8 | 11.3 | 11.0 | 12.9 | 14.6 | 13.4 | 14.4 | 152.3 |
| Average snowy days(≥ 0.1 in) | 17.7 | 12.5 | 8.9 | 4.5 | 0.2 | 0.0 | 0.0 | 0.0 | 0.0 | 0.6 | 7.7 | 12.5 | 64.6 |
| Mean monthlysunshine hours | 105.5 | 128.8 | 181.3 | 225.3 | 278.8 | 289.7 | 322.8 | 270.6 | 191.5 | 140.6 | 80.7 | 78.2 | 2,293.8 |
| Percentagepossible sunshine | 38 | 45 | 49 | 55 | 60 | 61 | 68 | 62 | 51 | 42 | 29 | 29 | 51 |
| Source:NOAA (sun 1961–1990)[18][19][20] | |||||||||||||
| Climate data for Sault Ste. Marie, Michigan (Sault Ste. Marie Municipal Airport) 1991–2020 normals,[e] extremes 1888–present | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °F (°C) | 48 (9) | 50 (10) | 83 (28) | 85 (29) | 91 (33) | 93 (34) | 98 (37) | 98 (37) | 95 (35) | 83 (28) | 74 (23) | 62 (17) | 98 (37) |
| Mean maximum °F (°C) | 39.3 (4.1) | 41.9 (5.5) | 52.5 (11.4) | 67.5 (19.7) | 81.8 (27.7) | 85.6 (29.8) | 87.7 (30.9) | 86.6 (30.3) | 81.6 (27.6) | 71.8 (22.1) | 56.4 (13.6) | 44.5 (6.9) | 89.4 (31.9) |
| Mean daily maximum °F (°C) | 24.0 (−4.4) | 26.4 (−3.1) | 35.5 (1.9) | 48.5 (9.2) | 63.2 (17.3) | 72.5 (22.5) | 76.8 (24.9) | 75.8 (24.3) | 68.0 (20.0) | 54.1 (12.3) | 41.2 (5.1) | 30.5 (−0.8) | 51.4 (10.8) |
| Daily mean °F (°C) | 16.2 (−8.8) | 17.8 (−7.9) | 26.7 (−2.9) | 39.4 (4.1) | 52.1 (11.2) | 61.1 (16.2) | 66.0 (18.9) | 65.6 (18.7) | 58.4 (14.7) | 46.3 (7.9) | 34.8 (1.6) | 23.8 (−4.6) | 42.4 (5.8) |
| Mean daily minimum °F (°C) | 8.4 (−13.1) | 9.3 (−12.6) | 17.9 (−7.8) | 30.2 (−1.0) | 41.0 (5.0) | 49.7 (9.8) | 55.2 (12.9) | 55.4 (13.0) | 48.7 (9.3) | 38.5 (3.6) | 28.3 (−2.1) | 17.1 (−8.3) | 33.3 (0.7) |
| Mean minimum °F (°C) | −14.0 (−25.6) | −11.1 (−23.9) | −4.4 (−20.2) | 15.9 (−8.9) | 29.8 (−1.2) | 37.4 (3.0) | 45.0 (7.2) | 45.0 (7.2) | 35.5 (1.9) | 26.7 (−2.9) | 10.4 (−12.0) | −5.1 (−20.6) | −17.6 (−27.6) |
| Record low °F (°C) | −36 (−38) | −37 (−38) | −28 (−33) | −13 (−25) | 18 (−8) | 26 (−3) | 36 (2) | 29 (−2) | 25 (−4) | 15 (−9) | −12 (−24) | −31 (−35) | −37 (−38) |
| Averageprecipitation inches (mm) | 2.21 (56) | 1.51 (38) | 1.81 (46) | 2.63 (67) | 2.64 (67) | 2.85 (72) | 3.07 (78) | 3.19 (81) | 3.93 (100) | 4.38 (111) | 3.44 (87) | 2.80 (71) | 34.46 (875) |
| Average snowfall inches (cm) | 30.3 (77) | 20.7 (53) | 13.0 (33) | 7.6 (19) | 0.4 (1.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 0.0 (0.0) | 1.7 (4.3) | 16.0 (41) | 30.4 (77) | 120.1 (305) |
| Average precipitation days(≥ 0.01 in) | 18.5 | 13.5 | 12.3 | 11.7 | 11.2 | 11.1 | 11.3 | 10.6 | 13.1 | 16.5 | 16.5 | 18.6 | 164.9 |
| Average snowy days(≥ 0.1 in) | 19.6 | 15.5 | 10.4 | 5.5 | 0.5 | 0.0 | 0.0 | 0.0 | 0.1 | 2.0 | 10.3 | 17.4 | 81.3 |
| Averagerelative humidity (%) | 77.2 | 75.2 | 74.7 | 69.9 | 67.9 | 74.7 | 76.3 | 79.6 | 81.6 | 80.4 | 81.7 | 81.0 | 76.7 |
| Averagedew point °F (°C) | 7.5 (−13.6) | 8.2 (−13.2) | 17.2 (−8.2) | 28.2 (−2.1) | 38.7 (3.7) | 49.3 (9.6) | 55.6 (13.1) | 55.6 (13.1) | 48.6 (9.2) | 38.3 (3.5) | 27.3 (−2.6) | 14.7 (−9.6) | 32.4 (0.2) |
| Mean monthlysunshine hours | 104.9 | 142.5 | 206.4 | 227.5 | 280.3 | 281.2 | 303.6 | 248.9 | 172.9 | 122.6 | 70.4 | 77.4 | 2,238.6 |
| Percentagepossible sunshine | 37 | 49 | 56 | 56 | 60 | 59 | 64 | 57 | 46 | 36 | 25 | 29 | 50 |
| Source:NOAA (relative humidity, dew point, and sun 1961–1990)[21][22][23] | |||||||||||||

The geological formation of the state is greatly varied. Primary boulders are found over the entire surface of the Upper Peninsula (being principally of primitive origin), while Secondary deposits cover the entire Lower Peninsula. The Upper Peninsula exhibits LowerSilurian sandstones, limestones, copper and iron bearing rocks, corresponding to the Huronian system ofCanada. The central portion of the Lower Peninsula contains coal measures and rocks of thePermo-Carboniferous period.Devonian and sub-Carboniferous deposits are scattered over the entire state.
The soil is of a varied composition and in large areas is very fertile, especially in the south. However, the Upper Peninsula for the most part is rocky and mountainous, and the soil is unsuitable for agriculture. The climate is tempered by the proximity of the lakes and is much milder than in other locales with the same latitude.
The principal forest trees includebasswood,maple,elm,sassafras,butternut,walnut,poplar,hickory,oak,willow,pine,birch,beech,hemlock,witchhazel,tamarack,cedar,locust,dogwood, andash.