S
M
T
W
T
F
S
30
68°
55°
31
70°
54°
1
70°
49°
2
69°
48°
3
64°
49°
4
63°
52°
5
67°
47°
6
66°
47°
7
65°
46°
8
61°
47°
9
61°
46°
10
60°
47°
11
60°
47°
12
61°
48°
13
64°
45°
14
65°
46°
15
60°
47°
16
60°
47°
17
61°
48°
18
63°
46°
19
59°
48°
20
60°
46°
21
Hist. Avg.
58°
44°
22
Hist. Avg.
58°
44°
23
Hist. Avg.
58°
44°
24
Hist. Avg.
57°
43°
25
Hist. Avg.
57°
43°
26
Hist. Avg.
57°
43°
27
Hist. Avg.
56°
43°
28
Hist. Avg.
56°
42°
29
Hist. Avg.
56°
42°
30
Hist. Avg.
56°
42°
1
Hist. Avg.
55°
42°
2
Hist. Avg.
55°
41°
3
Hist. Avg.
55°
41°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in St. John's
St. John's's September 2026 forecast shows daily high temperatures ranging from 59° to 70°, with overnight lows between 45° and 55°. The average high for September is 64° with an average low of 48°. 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.
