S
M
T
W
T
F
S
26
81°
60°
27
81°
62°
28
77°
61°
29
80°
60°
30
82°
62°
31
82°
57°
1
82°
61°
2
83°
62°
3
82°
57°
4
83°
55°
5
78°
60°
6
79°
61°
7
82°
60°
8
83°
56°
9
79°
55°
10
82°
61°
11
83°
54°
12
83°
55°
13
79°
61°
14
83°
62°
15
79°
58°
16
82°
54°
17
76°
53°
18
76°
53°
19
77°
54°
20
78°
56°
21
74°
53°
22
74°
59°
23
81°
60°
24
80°
59°
25
81°
51°
26
74°
50°
27
72°
50°
28
73°
51°
29
72°
52°
30
73°
57°
31
73°
59°
1
79°
59°
2
78°
56°
3
78°
54°
4
77°
57°
5
77°
49°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Waltham
Waltham's August 2026 forecast shows daily high temperatures ranging from 72° to 83°, with overnight lows between 49° and 62°. The average high for August is 79° with an average low of 57°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in Waltham. See also: September | October | November.
