S
M
T
W
T
F
S
26
81°
60°
27
82°
62°
28
79°
64°
29
79°
59°
30
81°
53°
31
85°
66°
1
78°
63°
2
72°
61°
3
75°
57°
4
79°
59°
5
81°
60°
6
81°
57°
7
80°
56°
8
80°
59°
9
80°
58°
10
78°
56°
11
77°
57°
12
76°
54°
13
79°
57°
14
78°
52°
15
71°
50°
16
71°
53°
17
72°
57°
18
72°
56°
19
73°
54°
20
71°
52°
21
71°
50°
22
70°
49°
23
69°
48°
24
69°
50°
25
70°
49°
26
70°
50°
27
69°
51°
28
69°
48°
29
70°
49°
30
71°
53°
31
74°
56°
1
71°
56°
2
73°
51°
3
68°
47°
4
67°
50°
5
70°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in St. Marys
St. Marys's August 2026 forecast shows daily high temperatures ranging from 67° to 85°, with overnight lows between 47° and 66°. The average high for August is 74° with an average low of 54°. 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. Marys. See also: September | October | November.