S
M
T
W
T
F
S
26
80°
65°
27
85°
67°
28
79°
66°
29
74°
65°
30
81°
62°
31
78°
63°
1
76°
67°
2
71°
61°
3
79°
61°
4
79°
62°
5
76°
65°
6
80°
69°
7
75°
71°
8
82°
70°
9
80°
65°
10
80°
71°
11
82°
69°
12
77°
67°
13
82°
63°
14
80°
61°
15
77°
64°
16
80°
64°
17
79°
60°
18
78°
62°
19
80°
66°
20
77°
63°
21
76°
60°
22
76°
62°
23
76°
62°
24
77°
60°
25
76°
60°
26
74°
59°
27
80°
64°
28
73°
59°
29
74°
62°
30
78°
63°
31
80°
63°
1
82°
64°
2
81°
63°
3
81°
62°
4
77°
62°
5
75°
61°
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 73° to 82°, with overnight lows between 59° and 66°. The average high for August is 78° with an average low of 62°. 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.
