S
M
T
W
T
F
S
30
62°
49°
31
62°
50°
1
63°
50°
2
61°
49°
3
61°
50°
4
62°
47°
5
62°
46°
6
61°
46°
7
62°
52°
8
60°
52°
9
64°
50°
10
61°
49°
11
60°
50°
12
61°
51°
13
62°
47°
14
60°
47°
15
59°
48°
16
60°
51°
17
62°
46°
18
62°
47°
19
60°
51°
20
60°
50°
21
62°
51°
22
62°
51°
23
61°
50°
24
60°
49°
25
60°
49°
26
59°
48°
27
59°
49°
28
60°
48°
29
60°
47°
30
56°
48°
1
58°
46°
2
60°
44°
3
Hist. Avg.
57°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Helensburgh
Helensburgh's September 2026 forecast shows daily high temperatures ranging from 56° to 64°, with overnight lows between 44° and 52°. The average high for September is 61° 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 Helensburgh. See also: October | November | December.
