S
M
T
W
T
F
S
30
78°
64°
31
82°
65°
1
81°
59°
2
78°
58°
3
78°
58°
4
79°
57°
5
77°
57°
6
79°
63°
7
82°
60°
8
78°
61°
9
82°
63°
10
82°
62°
11
80°
62°
12
81°
61°
13
82°
62°
14
82°
62°
15
81°
61°
16
81°
60°
17
78°
61°
18
79°
61°
19
80°
60°
20
80°
60°
21
79°
55°
22
78°
52°
23
74°
57°
24
71°
58°
25
Hist. Avg.
74°
56°
26
Hist. Avg.
74°
55°
27
Hist. Avg.
74°
55°
28
Hist. Avg.
73°
54°
29
Hist. Avg.
73°
54°
30
Hist. Avg.
72°
54°
1
Hist. Avg.
72°
53°
2
Hist. Avg.
71°
53°
3
Hist. Avg.
71°
52°
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 71° to 82°, with overnight lows between 52° and 65°. The average high for September is 79° with an average low of 60°. 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.
