S
M
T
W
T
F
S
30
73°
56°
31
76°
55°
1
78°
54°
2
78°
47°
3
73°
46°
4
70°
53°
5
70°
53°
6
77°
46°
7
71°
43°
8
67°
44°
9
68°
50°
10
70°
52°
11
69°
51°
12
76°
50°
13
75°
43°
14
67°
43°
15
64°
41°
16
65°
45°
17
65°
42°
18
66°
41°
19
67°
37°
20
62°
39°
21
63°
47°
22
64°
43°
23
71°
40°
24
68°
47°
25
70°
48°
26
69°
48°
27
71°
44°
28
71°
38°
29
67°
42°
30
58°
43°
1
65°
42°
2
68°
44°
3
58°
34°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Merrillan
Merrillan's September 2026 forecast shows daily high temperatures ranging from 58° to 78°, with overnight lows between 34° and 56°. The average high for September is 69° with an average low of 45°. 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 Merrillan. See also: October | November | December.
