S
M
T
W
T
F
S
30
92°
65°
31
94°
66°
1
94°
70°
2
93°
68°
3
93°
69°
4
92°
70°
5
92°
70°
6
91°
69°
7
93°
67°
8
91°
69°
9
85°
68°
10
90°
69°
11
91°
68°
12
92°
69°
13
92°
68°
14
91°
62°
15
90°
59°
16
81°
58°
17
80°
63°
18
83°
62°
19
81°
60°
20
80°
59°
21
79°
58°
22
80°
62°
23
83°
64°
24
85°
64°
25
86°
63°
26
86°
63°
27
87°
61°
28
84°
60°
29
83°
59°
30
84°
58°
1
82°
59°
2
84°
62°
3
77°
53°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Muenster
Muenster's September 2026 forecast shows daily high temperatures ranging from 77° to 94°, with overnight lows between 53° and 70°. The average high for September is 87° 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 Muenster. See also: October | November | December.