S
M
T
W
T
F
S
30
74°
44°
31
73°
47°
1
72°
47°
2
71°
49°
3
67°
58°
4
64°
57°
5
65°
51°
6
66°
47°
7
71°
49°
8
68°
49°
9
70°
48°
10
68°
50°
11
71°
50°
12
68°
51°
13
67°
49°
14
68°
41°
15
63°
51°
16
65°
52°
17
66°
51°
18
62°
50°
19
60°
48°
20
62°
49°
21
66°
50°
22
66°
50°
23
65°
50°
24
66°
49°
25
65°
48°
26
66°
49°
27
65°
48°
28
64°
47°
29
63°
46°
30
55°
43°
1
54°
43°
2
55°
46°
3
56°
46°
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 54° to 72°, with overnight lows between 41° and 58°. The average high for September is 65° with an average low of 49°. 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.
