S
M
T
W
T
F
S
30
66°
54°
31
63°
53°
1
65°
53°
2
67°
52°
3
66°
53°
4
62°
52°
5
62°
52°
6
61°
51°
7
60°
51°
8
61°
52°
9
62°
51°
10
61°
50°
11
62°
49°
12
62°
49°
13
60°
47°
14
60°
46°
15
59°
45°
16
56°
48°
17
59°
45°
18
58°
41°
19
55°
40°
20
54°
38°
21
54°
40°
22
53°
41°
23
56°
44°
24
55°
46°
25
54°
47°
26
58°
48°
27
58°
46°
28
57°
46°
29
57°
44°
30
56°
43°
1
54°
44°
2
52°
40°
3
53°
38°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Helsinki
Helsinki's September 2026 forecast shows daily high temperatures ranging from 52° to 67°, with overnight lows between 38° and 54°. The average high for September is 59° with an average low of 47°. 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 Helsinki. See also: October | November | December.
