Sister Islands (Wisconsin)

The Sister Islands are two islands in Lake Michigan. They are located in the bay of Green Bay, in the town of Liberty Grove, Wisconsin.[2] At one point the islands were connected, but higher water levels have eroded the size of the islands. Combined, the area of the islands sits at 6 acres (2.4 ha).

Sister Islands
In June 2020 when this picture was taken the average lake level was 177.45 meters above sea level;[1] the relatively high lake levels reduced the size of the islands that year.
Sister Islands is located in Wisconsin
Sister Islands
Sister Islands
Sister Islands is located in the United States
Sister Islands
Sister Islands
Geography
LocationGreen Bay, Lake Michigan
Coordinates45°13′28″N 87°08′46″W / 45.2244317°N 87.1462240°W / 45.2244317; -87.1462240
Area6 acres (2.4 ha)
Highest elevation581 ft (177.1 m)
Administration
StateWisconsin
CountyDoor County
TownLiberty Grove

There are many species of birds that nest on the islands. In 1964 there were an estimated 1,350 to 1,650 breeding pairs of herring gulls on the islands.[3] Both islands are owned and operated by the Wisconsin Department of Natural Resources, and they are protected as the Sister Islands State Natural Area.[4]

The shipwreck Meridian lies in the water south of the islands.[5]

Climate

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Sister Islands
Climate chart (explanation)
J
F
M
A
M
J
J
A
S
O
N
D
 
 
63
 
 
−5
−10
 
 
52
 
 
−9
−14
 
 
49
 
 
1
−6
 
 
97
 
 
6
0
 
 
86
 
 
11
3
 
 
91
 
 
15
9
 
 
105
 
 
20
16
 
 
96
 
 
20
14
 
 
96
 
 
17
14
 
 
107
 
 
9
6
 
 
80
 
 
8
2
 
 
57
 
 
3
−1
Average max. and min. temperatures in °C
Precipitation totals in mm
Source: [6]
Imperial conversion
JFMAMJJASOND
 
 
2.5
 
 
23
14
 
 
2
 
 
16
7
 
 
1.9
 
 
34
21
 
 
3.8
 
 
43
32
 
 
3.4
 
 
52
37
 
 
3.6
 
 
59
48
 
 
4.1
 
 
68
61
 
 
3.8
 
 
68
57
 
 
3.8
 
 
63
57
 
 
4.2
 
 
48
43
 
 
3.1
 
 
46
36
 
 
2.2
 
 
37
30
Average max. and min. temperatures in °F
Precipitation totals in inches

Diagram

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Big and Little Sister islands, as drawn from photos taken in 1976
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References

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  1. ^ Lake Michigan-Huron: Monthly Lake-Wide Average Water Levels (1918 - Present), Great Lakes Environmental Research Laboratory, National Oceanic and Atmospheric Administration, accessed February 25, 2022
  2. ^ "Report For Sister Islands". USGNIS. Retrieved 17 April 2018.
  3. ^ Town of Liberty Grove Comprehensive Plan 2003, Part 2, page 29 (page 3 of the pdf)
  4. ^ "Sister Islands". Wisconsin DNR. Retrieved 17 April 2018.
  5. ^ "Final Voyage". Wisconsin's Great Lake Shipwrecks. Archived from the original on 2 December 2010. Retrieved 17 April 2018.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  6. ^ "NASA EarthData Search". NASA. Retrieved 30 January 2016.
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