S
M
T
W
T
F
S
30
83°
55°
31
79°
56°
1
70°
59°
2
75°
59°
3
77°
61°
4
84°
60°
5
73°
56°
6
71°
50°
7
80°
47°
8
79°
52°
9
80°
52°
10
85°
67°
11
76°
49°
12
78°
42°
13
71°
62°
14
73°
47°
15
71°
40°
16
79°
48°
17
82°
61°
18
78°
58°
19
66°
43°
20
62°
47°
21
69°
51°
22
65°
44°
23
66°
40°
24
66°
38°
25
68°
55°
26
61°
52°
27
59°
53°
28
60°
54°
29
67°
52°
30
74°
53°
1
78°
55°
2
78°
53°
3
73°
49°
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 59° to 78°, with overnight lows between 49° and 55°. The average high for September is 69° with an average low of 53°. 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.
