S
M
T
W
T
F
S
26
97°
74°
27
97°
78°
28
91°
75°
29
87°
68°
30
89°
65°
31
79°
69°
1
76°
69°
2
82°
67°
3
88°
64°
4
89°
67°
5
90°
70°
6
85°
70°
7
84°
68°
8
90°
72°
9
95°
73°
10
96°
75°
11
95°
76°
12
93°
74°
13
94°
73°
14
94°
71°
15
92°
73°
16
89°
68°
17
93°
75°
18
93°
76°
19
94°
75°
20
93°
74°
21
91°
73°
22
92°
74°
23
90°
74°
24
89°
73°
25
90°
73°
26
88°
72°
27
89°
72°
28
90°
71°
29
90°
72°
30
89°
71°
31
89°
71°
1
90°
70°
2
90°
71°
3
89°
70°
4
88°
69°
5
89°
71°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in St. Louis
St. Louis's August 2026 forecast shows daily high temperatures ranging from 84° to 96°, with overnight lows between 64° and 76°. The average high for August is 91° with an average low of 72°. 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. Louis. See also: September | October | November.