S
M
T
W
T
F
S
30
74°
54°
31
81°
50°
1
74°
51°
2
75°
50°
3
73°
57°
4
77°
56°
5
80°
57°
6
81°
56°
7
71°
49°
8
71°
49°
9
72°
51°
10
73°
54°
11
77°
54°
12
78°
57°
13
70°
56°
14
73°
58°
15
70°
55°
16
70°
55°
17
71°
50°
18
69°
56°
19
69°
52°
20
72°
48°
21
71°
47°
22
68°
48°
23
68°
51°
24
73°
52°
25
74°
53°
26
Hist. Avg.
73°
48°
27
Hist. Avg.
72°
47°
28
Hist. Avg.
72°
47°
29
Hist. Avg.
71°
47°
30
Hist. Avg.
71°
47°
1
Hist. Avg.
70°
46°
2
Hist. Avg.
70°
46°
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 St. Helens
St. Helens's September 2026 forecast shows daily high temperatures ranging from 68° to 81°, with overnight lows between 47° and 58°. The average high for September is 73° with an average low of 53°. 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.
