S
M
T
W
T
F
S
26
61°
31°
27
63°
34°
28
57°
32°
29
44°
39°
30
46°
41°
1
59°
36°
2
50°
30°
3
45°
39°
4
59°
36°
5
58°
45°
6
55°
49°
7
60°
39°
8
57°
38°
9
58°
31°
10
55°
47°
11
61°
45°
12
56°
40°
13
55°
40°
14
64°
46°
15
60°
51°
16
69°
48°
17
80°
52°
18
62°
48°
19
77°
45°
20
87°
55°
21
64°
46°
22
67°
35°
23
63°
37°
24
58°
39°
25
66°
47°
26
75°
48°
27
83°
53°
28
61°
43°
29
58°
41°
30
53°
38°
31
63°
41°
1
60°
44°
2
61°
43°
3
68°
48°
4
76°
52°
5
74°
52°
6
70°
53°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Waltham
Waltham's May 2026 forecast shows daily high temperatures ranging from 53° to 83°, with overnight lows between 38° and 53°. The average high for May is 66° 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 May weather will actually feel in Waltham. See also: June | July | August.
