S
M
T
W
T
F
S
26
57°
39°
27
58°
39°
28
59°
42°
29
59°
39°
30
58°
38°
1
58°
43°
2
59°
40°
3
60°
41°
4
61°
47°
5
69°
46°
6
65°
42°
7
61°
44°
8
68°
49°
9
72°
50°
10
72°
46°
11
63°
43°
12
62°
45°
13
64°
47°
14
63°
47°
15
62°
46°
16
63°
49°
17
64°
50°
18
72°
42°
19
66°
47°
20
70°
47°
21
69°
44°
22
68°
43°
23
67°
44°
24
67°
44°
25
70°
45°
26
69°
46°
27
69°
47°
28
70°
46°
29
70°
49°
30
71°
52°
31
71°
48°
1
72°
55°
2
72°
52°
3
73°
51°
4
73°
56°
5
78°
55°
6
76°
50°
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 57° to 78°, with overnight lows between 38° and 56°. 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.
