S
M
T
W
T
F
S
30
80°
65°
31
76°
68°
1
90°
69°
2
92°
73°
3
87°
68°
4
77°
68°
5
78°
54°
6
76°
53°
7
78°
54°
8
82°
68°
9
84°
61°
10
77°
54°
11
76°
58°
12
78°
61°
13
81°
58°
14
76°
51°
15
82°
60°
16
78°
56°
17
77°
58°
18
79°
42°
19
77°
57°
20
78°
57°
21
72°
55°
22
67°
54°
23
68°
55°
24
71°
55°
25
76°
54°
26
75°
54°
27
71°
53°
28
75°
55°
29
76°
56°
30
76°
56°
1
75°
53°
2
73°
49°
3
61°
45°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Mason
Mason's September 2026 forecast shows daily high temperatures ranging from 61° to 84°, with overnight lows between 42° and 68°. The average high for September is 76° with an average low of 55°. 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 Mason. See also: October | November | December.