S
M
T
W
T
F
S
26
80°
64°
27
81°
63°
28
81°
64°
29
79°
62°
30
81°
63°
31
76°
60°
1
75°
57°
2
76°
59°
3
77°
61°
4
78°
60°
5
80°
62°
6
82°
63°
7
83°
64°
8
84°
63°
9
83°
62°
10
83°
62°
11
82°
61°
12
83°
63°
13
82°
64°
14
83°
54°
15
75°
59°
16
76°
54°
17
75°
53°
18
78°
53°
19
77°
50°
20
73°
50°
21
73°
52°
22
74°
52°
23
74°
50°
24
75°
56°
25
76°
55°
26
80°
57°
27
80°
54°
28
82°
50°
29
73°
49°
30
70°
50°
31
70°
50°
1
71°
48°
2
70°
50°
3
72°
48°
4
73°
52°
5
71°
53°
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 70° to 84°, with overnight lows between 48° and 64°. The average high for August is 77° 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.
