S
M
T
W
T
F
S
30
67°
57°
31
68°
56°
1
66°
56°
2
65°
57°
3
66°
56°
4
66°
55°
5
65°
54°
6
64°
52°
7
64°
56°
8
63°
56°
9
63°
54°
10
65°
55°
11
65°
56°
12
66°
56°
13
64°
54°
14
65°
54°
15
66°
56°
16
64°
55°
17
65°
54°
18
60°
54°
19
61°
51°
20
61°
55°
21
62°
55°
22
62°
54°
23
Hist. Avg.
61°
50°
24
Hist. Avg.
61°
50°
25
Hist. Avg.
61°
49°
26
Hist. Avg.
61°
49°
27
Hist. Avg.
61°
49°
28
Hist. Avg.
60°
49°
29
Hist. Avg.
60°
49°
30
Hist. Avg.
60°
49°
1
Hist. Avg.
60°
48°
2
Hist. Avg.
60°
48°
3
Hist. Avg.
59°
48°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Waltham
Waltham's September 2026 forecast shows daily high temperatures ranging from 60° to 68°, with overnight lows between 51° and 57°. The average high for September is 64° with an average low of 55°. 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 Waltham. See also: October | November | December.
