S
M
T
W
T
F
S
26
45°
31°
27
52°
30°
28
55°
21°
29
57°
18°
30
57°
21°
1
55°
16°
2
62°
18°
3
66°
21°
4
59°
28°
5
57°
15°
6
61°
28°
7
70°
21°
8
74°
30°
9
72°
29°
10
73°
24°
11
79°
23°
12
81°
32°
13
78°
36°
14
74°
26°
15
75°
34°
16
71°
31°
17
64°
26°
18
45°
25°
19
56°
16°
20
65°
42°
21
73°
44°
22
65°
49°
23
73°
49°
24
76°
51°
25
73°
54°
26
69°
49°
27
68°
44°
28
64°
45°
29
75°
51°
30
77°
49°
31
77°
51°
1
74°
52°
2
74°
50°
3
74°
55°
4
73°
53°
5
74°
55°
6
76°
55°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Boulder
Boulder's May 2026 forecast shows daily high temperatures ranging from 64° to 77°, with overnight lows between 42° and 55°. The average high for May is 72° with an average low of 50°. 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 Boulder. See also: June | July | August.
