S
M
T
W
T
F
S
30
92°
66°
31
92°
66°
1
89°
65°
2
88°
64°
3
84°
59°
4
83°
59°
5
83°
64°
6
87°
63°
7
88°
64°
8
87°
63°
9
87°
63°
10
88°
62°
11
84°
56°
12
80°
56°
13
80°
61°
14
84°
61°
15
81°
62°
16
81°
61°
17
82°
60°
18
84°
58°
19
78°
51°
20
76°
52°
21
76°
53°
22
77°
55°
23
80°
58°
24
82°
59°
25
82°
56°
26
82°
50°
27
77°
51°
28
74°
49°
29
73°
48°
30
74°
55°
1
73°
57°
2
Hist. Avg.
77°
52°
3
Hist. Avg.
77°
51°
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 73° to 92°, with overnight lows between 48° and 66°. The average high for September is 82° with an average low of 58°. 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.
