S
M
T
W
T
F
S
30
79°
53°
31
78°
52°
1
79°
53°
2
78°
53°
3
77°
51°
4
75°
49°
5
71°
47°
6
75°
45°
7
69°
43°
8
68°
44°
9
72°
42°
10
74°
41°
11
71°
42°
12
70°
46°
13
72°
51°
14
77°
47°
15
79°
45°
16
75°
50°
17
76°
53°
18
76°
50°
19
69°
50°
20
74°
51°
21
75°
49°
22
66°
47°
23
64°
41°
24
67°
44°
25
69°
44°
26
70°
45°
27
67°
39°
28
64°
43°
29
68°
44°
30
67°
41°
1
65°
42°
2
70°
48°
3
70°
39°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Rainier
Rainier's September 2026 forecast shows daily high temperatures ranging from 64° to 79°, with overnight lows between 39° and 53°. The average high for September is 72° with an average low of 46°. 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 Rainier. See also: October | November | December.
