S
M
T
W
T
F
S
26
45°
36°
27
45°
36°
28
51°
35°
29
43°
32°
30
41°
32°
1
46°
28°
2
51°
36°
3
55°
37°
4
50°
32°
5
44°
32°
6
45°
31°
7
46°
32°
8
49°
33°
9
51°
34°
10
52°
34°
11
55°
37°
12
57°
38°
13
51°
35°
14
52°
34°
15
52°
37°
16
53°
36°
17
53°
38°
18
54°
37°
19
54°
40°
20
58°
39°
21
55°
38°
22
54°
35°
23
52°
36°
24
55°
40°
25
56°
38°
26
57°
40°
27
56°
42°
28
55°
40°
29
57°
40°
30
58°
38°
31
57°
38°
1
57°
40°
2
58°
38°
3
58°
44°
4
57°
43°
5
59°
44°
6
59°
44°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Thunder Bay
Thunder Bay's May 2026 forecast shows daily high temperatures ranging from 41° to 59°, with overnight lows between 28° and 44°. The average high for May is 53° with an average low of 37°. 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 Thunder Bay. See also: June | July | August.
