S
M
T
W
T
F
S
30
66°
49°
31
65°
46°
1
64°
46°
2
64°
47°
3
65°
46°
4
66°
49°
5
66°
51°
6
65°
47°
7
64°
46°
8
62°
47°
9
63°
44°
10
63°
50°
11
65°
47°
12
63°
47°
13
65°
44°
14
65°
45°
15
66°
44°
16
64°
42°
17
66°
42°
18
66°
48°
19
67°
50°
20
64°
49°
21
66°
49°
22
66°
48°
23
65°
46°
24
64°
43°
25
59°
44°
26
63°
41°
27
63°
40°
28
57°
39°
29
55°
39°
30
55°
38°
1
Hist. Avg.
58°
41°
2
Hist. Avg.
58°
41°
3
Hist. Avg.
58°
41°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Saint John
Saint John's September 2026 forecast shows daily high temperatures ranging from 55° to 67°, with overnight lows between 38° and 51°. The average high for September is 64° with an average low of 45°. 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 Saint John. See also: October | November | December.
