S
M
T
W
T
F
S
30
77°
56°
31
77°
55°
1
75°
54°
2
73°
54°
3
76°
56°
4
77°
55°
5
76°
55°
6
76°
54°
7
75°
54°
8
74°
52°
9
73°
52°
10
73°
53°
11
75°
52°
12
71°
51°
13
63°
46°
14
60°
42°
15
61°
49°
16
62°
48°
17
63°
43°
18
68°
47°
19
70°
48°
20
71°
49°
21
70°
49°
22
63°
37°
23
68°
40°
24
68°
43°
25
67°
47°
26
65°
39°
27
65°
33°
28
58°
36°
29
61°
41°
30
64°
43°
1
59°
39°
2
56°
45°
3
60°
45°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Mercer
Mercer's September 2026 forecast shows daily high temperatures ranging from 56° to 77°, with overnight lows between 33° and 56°. The average high for September is 68° with an average low of 47°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in Mercer. See also: October | November | December.
