S
M
T
W
T
F
S
30
81°
63°
31
80°
64°
1
83°
67°
2
81°
65°
3
82°
65°
4
83°
69°
5
85°
69°
6
86°
70°
7
87°
69°
8
86°
68°
9
83°
67°
10
83°
68°
11
84°
68°
12
84°
67°
13
81°
67°
14
76°
66°
15
76°
66°
16
75°
63°
17
75°
61°
18
78°
64°
19
79°
64°
20
79°
61°
21
84°
64°
22
84°
58°
23
82°
56°
24
75°
58°
25
73°
59°
26
72°
62°
27
79°
61°
28
80°
61°
29
81°
59°
30
80°
59°
1
78°
58°
2
78°
60°
3
80°
60°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Chester
Chester's September 2026 forecast shows daily high temperatures ranging from 72° to 87°, with overnight lows between 56° and 70°. The average high for September is 80° with an average low of 64°. 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 Chester. See also: October | November | December.