S
M
T
W
T
F
S
30
79°
60°
31
80°
61°
1
85°
55°
2
79°
55°
3
79°
56°
4
80°
54°
5
79°
53°
6
80°
56°
7
82°
54°
8
80°
59°
9
83°
58°
10
79°
58°
11
80°
57°
12
82°
57°
13
82°
56°
14
83°
57°
15
83°
56°
16
82°
54°
17
80°
55°
18
74°
56°
19
80°
55°
20
81°
55°
21
80°
53°
22
79°
47°
23
76°
53°
24
Hist. Avg.
74°
50°
25
Hist. Avg.
73°
50°
26
Hist. Avg.
73°
49°
27
Hist. Avg.
72°
49°
28
Hist. Avg.
72°
48°
29
Hist. Avg.
72°
48°
30
Hist. Avg.
71°
48°
1
Hist. Avg.
71°
47°
2
Hist. Avg.
70°
47°
3
Hist. Avg.
70°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Mainland
Mainland's September 2026 forecast shows daily high temperatures ranging from 74° to 85°, with overnight lows between 47° and 61°. The average high for September is 80° with an average low of 56°. 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 Mainland. See also: October | November | December.
