S
M
T
W
T
F
S
30
66°
55°
31
68°
55°
1
67°
54°
2
67°
53°
3
64°
52°
4
61°
52°
5
61°
53°
6
65°
52°
7
61°
47°
8
60°
47°
9
66°
52°
10
64°
53°
11
65°
53°
12
66°
52°
13
64°
52°
14
61°
44°
15
63°
45°
16
58°
45°
17
58°
44°
18
61°
44°
19
61°
48°
20
57°
46°
21
62°
48°
22
57°
42°
23
62°
43°
24
55°
42°
25
57°
41°
26
54°
45°
27
58°
44°
28
57°
43°
29
54°
43°
30
54°
39°
1
58°
39°
2
51°
40°
3
58°
39°
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 51° to 68°, with overnight lows between 39° and 55°. The average high for September is 61° 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 St. John's. See also: October | November | December.
