S
M
T
W
T
F
S
28
67°
53°
29
66°
57°
30
83°
59°
1
81°
59°
2
76°
61°
3
75°
60°
4
78°
60°
5
78°
59°
6
77°
59°
7
78°
57°
8
77°
50°
9
68°
54°
10
69°
54°
11
73°
55°
12
72°
55°
13
70°
54°
14
75°
56°
15
75°
56°
16
70°
55°
17
76°
56°
18
73°
55°
19
70°
55°
20
71°
56°
21
74°
56°
22
75°
57°
23
77°
56°
24
71°
55°
25
69°
54°
26
77°
56°
27
70°
56°
28
75°
57°
29
77°
56°
30
70°
55°
31
70°
55°
1
71°
56°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
July Weather in Thunder Bay
Thunder Bay's July 2026 forecast shows daily high temperatures ranging from 66° to 83°, with overnight lows between 50° and 61°. The average high for July is 74° with an average low of 56°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how July weather will actually feel in Thunder Bay. See also: August | September | October.