S
M
T
W
T
F
S
30
77°
53°
31
76°
53°
1
77°
51°
2
81°
57°
3
84°
51°
4
79°
54°
5
75°
51°
6
81°
49°
7
75°
48°
8
78°
49°
9
79°
52°
10
80°
56°
11
82°
45°
12
78°
48°
13
73°
52°
14
74°
54°
15
77°
42°
16
81°
42°
17
69°
41°
18
68°
40°
19
68°
42°
20
68°
46°
21
73°
42°
22
71°
41°
23
66°
39°
24
65°
38°
25
65°
38°
26
66°
40°
27
66°
39°
28
65°
42°
29
64°
38°
30
68°
40°
1
67°
34°
2
Hist. Avg.
65°
39°
3
Hist. Avg.
65°
39°
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 64° to 84°, with overnight lows between 34° and 57°. The average high for September is 73° with an average low of 46°. 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.
