S
M
T
W
T
F
S
26
85°
64°
27
84°
63°
28
85°
65°
29
85°
61°
30
81°
66°
31
82°
67°
1
84°
65°
2
86°
67°
3
86°
68°
4
87°
67°
5
87°
65°
6
82°
62°
7
87°
67°
8
88°
66°
9
84°
67°
10
88°
66°
11
84°
63°
12
86°
66°
13
86°
67°
14
85°
63°
15
80°
60°
16
79°
59°
17
79°
64°
18
78°
66°
19
80°
66°
20
82°
65°
21
81°
65°
22
82°
64°
23
80°
63°
24
87°
62°
25
85°
64°
26
86°
62°
27
82°
63°
28
83°
64°
29
78°
58°
30
78°
56°
31
77°
57°
1
77°
62°
2
75°
63°
3
84°
63°
4
84°
62°
5
83°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Mercersburg
Mercersburg's August 2026 forecast shows daily high temperatures ranging from 75° to 88°, with overnight lows between 56° and 68°. The average high for August is 83° with an average low of 64°. 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 Mercersburg. See also: September | October | November.
