S
M
T
W
T
F
S
30
85°
65°
31
86°
65°
1
86°
66°
2
87°
67°
3
88°
67°
4
89°
66°
5
88°
69°
6
85°
68°
7
84°
66°
8
88°
67°
9
87°
68°
10
88°
67°
11
88°
67°
12
87°
66°
13
87°
67°
14
86°
65°
15
88°
66°
16
Hist. Avg.
86°
64°
17
Hist. Avg.
86°
64°
18
Hist. Avg.
86°
64°
19
Hist. Avg.
86°
64°
20
Hist. Avg.
86°
63°
21
Hist. Avg.
85°
63°
22
Hist. Avg.
85°
63°
23
Hist. Avg.
85°
62°
24
Hist. Avg.
85°
62°
25
Hist. Avg.
84°
62°
26
Hist. Avg.
84°
61°
27
Hist. Avg.
84°
61°
28
Hist. Avg.
84°
60°
29
Hist. Avg.
83°
60°
30
Hist. Avg.
83°
60°
1
Hist. Avg.
83°
59°
2
Hist. Avg.
83°
59°
3
Hist. Avg.
82°
58°
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 84° to 89°, with overnight lows between 65° and 69°. The average high for September is 87° with an average low of 67°. 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.
