S
M
T
W
T
F
S
30
75°
51°
31
76°
51°
1
74°
52°
2
73°
53°
3
74°
54°
4
72°
54°
5
73°
53°
6
74°
52°
7
72°
51°
8
73°
49°
9
71°
50°
10
72°
56°
11
71°
50°
12
72°
49°
13
75°
48°
14
73°
55°
15
73°
54°
16
71°
49°
17
69°
47°
18
70°
47°
19
70°
52°
20
72°
53°
21
73°
52°
22
69°
51°
23
73°
51°
24
72°
50°
25
71°
51°
26
66°
43°
27
70°
45°
28
64°
44°
29
63°
44°
30
65°
46°
1
65°
43°
2
62°
40°
3
Hist. Avg.
67°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Monson
Monson's September 2026 forecast shows daily high temperatures ranging from 62° to 76°, with overnight lows between 40° and 56°. The average high for September is 71° with an average low of 50°. 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 Monson. See also: October | November | December.