S
M
T
W
T
F
S
30
90°
64°
31
87°
63°
1
81°
61°
2
83°
57°
3
79°
56°
4
80°
60°
5
81°
63°
6
86°
61°
7
87°
62°
8
80°
61°
9
84°
61°
10
85°
54°
11
77°
53°
12
77°
53°
13
78°
54°
14
78°
60°
15
83°
60°
16
81°
59°
17
82°
59°
18
76°
51°
19
75°
50°
20
73°
54°
21
73°
54°
22
77°
56°
23
79°
57°
24
80°
58°
25
81°
49°
26
80°
48°
27
72°
49°
28
71°
48°
29
71°
48°
30
73°
55°
1
69°
48°
2
70°
45°
3
Hist. Avg.
75°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Dorchester
Dorchester's September 2026 forecast shows daily high temperatures ranging from 69° to 90°, with overnight lows between 45° and 64°. The average high for September is 79° with an average low of 56°. 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 Dorchester. See also: October | November | December.
