S
M
T
W
T
F
S
26
80°
67°
27
85°
67°
28
82°
66°
29
83°
67°
30
81°
63°
31
77°
61°
1
78°
65°
2
81°
67°
3
85°
68°
4
86°
67°
5
83°
66°
6
82°
66°
7
82°
65°
8
84°
65°
9
84°
58°
10
78°
56°
11
76°
58°
12
78°
59°
13
77°
56°
14
77°
58°
15
78°
63°
16
77°
62°
17
81°
61°
18
77°
57°
19
78°
61°
20
81°
62°
21
81°
64°
22
82°
63°
23
80°
63°
24
82°
59°
25
79°
55°
26
76°
56°
27
75°
62°
28
78°
60°
29
78°
61°
30
79°
62°
31
75°
54°
1
76°
55°
2
75°
52°
3
72°
52°
4
73°
53°
5
76°
55°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in St. Catharines
St. Catharines's August 2026 forecast shows daily high temperatures ranging from 72° to 86°, with overnight lows between 52° and 68°. The average high for August is 79° with an average low of 61°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in St. Catharines. See also: September | October | November.
