S
M
T
W
T
F
S
26
83°
67°
27
84°
66°
28
80°
66°
29
78°
65°
30
81°
67°
31
84°
68°
1
84°
67°
2
82°
65°
3
86°
66°
4
86°
60°
5
80°
59°
6
79°
60°
7
80°
61°
8
76°
62°
9
76°
60°
10
77°
60°
11
78°
65°
12
83°
65°
13
79°
58°
14
78°
57°
15
77°
56°
16
77°
63°
17
79°
61°
18
77°
57°
19
77°
56°
20
78°
56°
21
78°
58°
22
83°
63°
23
83°
63°
24
84°
64°
25
84°
62°
26
82°
63°
27
84°
59°
28
81°
63°
29
82°
61°
30
78°
55°
31
75°
52°
1
72°
53°
2
72°
51°
3
71°
52°
4
72°
52°
5
71°
53°
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 71° to 86°, with overnight lows between 51° and 68°. The average high for August is 79° with an average low of 60°. 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.
