S
M
T
W
T
F
S
30
71°
60°
31
69°
54°
1
60°
51°
2
55°
42°
3
66°
51°
4
66°
52°
5
59°
53°
6
58°
54°
7
62°
53°
8
61°
52°
9
63°
49°
10
64°
55°
11
65°
55°
12
66°
55°
13
64°
53°
14
65°
49°
15
63°
50°
16
58°
50°
17
61°
51°
18
63°
50°
19
63°
48°
20
57°
49°
21
61°
50°
22
63°
49°
23
61°
50°
24
62°
48°
25
58°
48°
26
58°
47°
27
60°
48°
28
61°
49°
29
61°
49°
30
60°
48°
1
58°
47°
2
59°
46°
3
53°
45°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in St. John's
St. John's's September 2026 forecast shows daily high temperatures ranging from 53° to 66°, with overnight lows between 42° and 55°. The average high for September is 61° 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 St. John's. See also: October | November | December.
