S
M
T
W
T
F
S
30
80°
55°
31
78°
55°
1
82°
54°
2
81°
55°
3
79°
53°
4
77°
51°
5
74°
50°
6
77°
50°
7
74°
46°
8
73°
46°
9
76°
46°
10
78°
45°
11
75°
44°
12
73°
49°
13
76°
54°
14
81°
54°
15
83°
49°
16
77°
52°
17
80°
56°
18
80°
53°
19
73°
53°
20
78°
55°
21
79°
50°
22
71°
49°
23
69°
45°
24
71°
48°
25
72°
47°
26
75°
47°
27
74°
43°
28
68°
47°
29
71°
49°
30
72°
48°
1
71°
46°
2
75°
51°
3
75°
47°
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 68° to 83°, with overnight lows between 43° and 56°. The average high for September is 76° 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 Rainier. See also: October | November | December.
