S
M
T
W
T
F
S
30
74°
58°
31
70°
56°
1
78°
64°
2
75°
59°
3
75°
53°
4
75°
51°
5
74°
52°
6
74°
49°
7
80°
52°
8
73°
60°
9
75°
58°
10
66°
44°
11
73°
39°
12
74°
52°
13
66°
44°
14
62°
41°
15
63°
47°
16
69°
46°
17
71°
49°
18
60°
41°
19
63°
38°
20
62°
42°
21
52°
38°
22
62°
36°
23
66°
39°
24
69°
42°
25
69°
42°
26
71°
45°
27
72°
45°
28
75°
46°
29
69°
51°
30
66°
49°
1
63°
46°
2
62°
45°
3
62°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Chelmsford
Chelmsford's September 2026 forecast shows daily high temperatures ranging from 62° to 75°, with overnight lows between 42° and 51°. The average high for September is 68° with an average low of 46°. 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 Chelmsford. See also: October | November | December.
