S
M
T
W
T
F
S
30
71°
60°
31
69°
56°
1
69°
54°
2
71°
60°
3
72°
66°
4
66°
59°
5
66°
45°
6
75°
57°
7
66°
61°
8
N/A
9
63°
54°
10
64°
56°
11
64°
51°
12
66°
59°
13
67°
59°
14
68°
60°
15
64°
54°
16
63°
55°
17
64°
55°
18
64°
56°
19
65°
56°
20
64°
55°
21
64°
58°
22
64°
57°
23
63°
57°
24
64°
56°
25
60°
53°
26
60°
55°
27
62°
52°
28
61°
52°
29
60°
55°
30
62°
56°
1
62°
55°
2
61°
55°
3
61°
56°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Johnston
Johnston's September 2026 forecast shows daily high temperatures ranging from 60° to 68°, with overnight lows between 51° and 60°. The average high for September is 63° with an average low of 55°. 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 Johnston. See also: October | November | December.
