S
M
T
W
T
F
S
26
55°
39°
27
68°
43°
28
64°
50°
29
54°
35°
30
49°
31°
1
46°
29°
2
52°
27°
3
68°
39°
4
80°
45°
5
60°
44°
6
57°
31°
7
54°
32°
8
62°
31°
9
73°
40°
10
58°
32°
11
51°
32°
12
70°
31°
13
55°
36°
14
62°
34°
15
75°
51°
16
83°
58°
17
69°
52°
18
82°
60°
19
79°
55°
20
58°
44°
21
54°
45°
22
63°
48°
23
63°
50°
24
75°
53°
25
81°
52°
26
81°
55°
27
70°
52°
28
65°
49°
29
72°
53°
30
68°
52°
31
68°
54°
1
72°
51°
2
74°
54°
3
77°
56°
4
76°
59°
5
75°
59°
6
76°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Winthrop Harbor
Winthrop Harbor's May 2026 forecast shows daily high temperatures ranging from 65° to 77°, with overnight lows between 49° and 59°. The average high for May is 72° with an average low of 54°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how May weather will actually feel in Winthrop Harbor. See also: June | July | August.
