S
M
T
W
T
F
S
30
73°
47°
31
87°
58°
1
67°
56°
2
65°
54°
3
63°
52°
4
67°
49°
5
72°
50°
6
69°
51°
7
73°
49°
8
81°
50°
9
87°
52°
10
77°
53°
11
71°
49°
12
64°
52°
13
65°
53°
14
68°
53°
15
70°
52°
16
81°
53°
17
84°
50°
18
68°
45°
19
75°
50°
20
78°
50°
21
72°
55°
22
73°
50°
23
70°
48°
24
71°
55°
25
64°
45°
26
69°
47°
27
72°
46°
28
68°
50°
29
67°
51°
30
70°
53°
1
69°
48°
2
65°
49°
3
67°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in St. Helens
St. Helens's September 2026 forecast shows daily high temperatures ranging from 64° to 72°, with overnight lows between 45° and 55°. The average high for September is 68° with an average low of 49°. 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 St. Helens. See also: October | November | December.
