S
M
T
W
T
F
S
30
90°
71°
31
88°
67°
1
86°
61°
2
82°
60°
3
82°
61°
4
83°
62°
5
90°
61°
6
75°
64°
7
88°
74°
8
95°
73°
9
103°
75°
10
100°
73°
11
96°
67°
12
90°
64°
13
88°
64°
14
89°
63°
15
90°
65°
16
88°
66°
17
89°
65°
18
88°
64°
19
88°
64°
20
87°
61°
21
83°
60°
22
82°
60°
23
82°
59°
24
83°
59°
25
83°
60°
26
84°
60°
27
81°
59°
28
84°
61°
29
86°
61°
30
87°
62°
1
87°
61°
2
86°
61°
3
88°
60°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Montclair
Montclair's September 2026 forecast shows daily high temperatures ranging from 81° to 103°, with overnight lows between 59° and 75°. The average high for September is 88° 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 September weather will actually feel in Montclair. See also: October | November | December.
