S
M
T
W
T
F
S
30
89°
77°
31
90°
76°
1
89°
77°
2
89°
78°
3
90°
78°
4
90°
77°
5
89°
78°
6
88°
78°
7
89°
77°
8
88°
78°
9
89°
77°
10
89°
77°
11
90°
78°
12
90°
77°
13
89°
76°
14
89°
75°
15
88°
77°
16
88°
77°
17
89°
76°
18
89°
78°
19
90°
78°
20
89°
77°
21
90°
78°
22
89°
77°
23
89°
76°
24
88°
77°
25
88°
77°
26
88°
76°
27
89°
78°
28
90°
77°
29
89°
77°
30
Hist. Avg.
89°
75°
1
Hist. Avg.
89°
74°
2
Hist. Avg.
89°
74°
3
Hist. Avg.
89°
74°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Saint John
Saint John's September 2026 forecast shows daily high temperatures ranging from 88° to 90°, with overnight lows between 75° and 78°. The average high for September is 89° with an average low of 77°. 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.
