S
M
T
W
T
F
S
30
89°
80°
31
91°
80°
1
90°
78°
2
89°
80°
3
89°
80°
4
90°
79°
5
89°
80°
6
90°
79°
7
89°
79°
8
89°
80°
9
88°
79°
10
89°
80°
11
89°
81°
12
90°
80°
13
90°
80°
14
89°
79°
15
89°
80°
16
90°
80°
17
89°
79°
18
90°
80°
19
89°
78°
20
89°
79°
21
88°
78°
22
88°
78°
23
89°
80°
24
90°
80°
25
Hist. Avg.
89°
75°
26
Hist. Avg.
89°
75°
27
Hist. Avg.
89°
75°
28
Hist. Avg.
89°
75°
29
Hist. Avg.
89°
75°
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 St John
St John's September 2026 forecast shows daily high temperatures ranging from 88° to 91°, with overnight lows between 78° and 81°. The average high for September is 89° with an average low of 79°. 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. See also: October | November | December.
