S
M
T
W
T
F
S
26
51°
37°
27
55°
35°
28
61°
38°
29
58°
31°
30
49°
34°
1
64°
28°
2
73°
30°
3
76°
39°
4
74°
38°
5
47°
32°
6
41°
30°
7
72°
29°
8
71°
40°
9
76°
44°
10
69°
46°
11
87°
40°
12
77°
53°
13
87°
44°
14
87°
55°
15
83°
46°
16
78°
54°
17
66°
44°
18
66°
39°
19
50°
37°
20
57°
43°
21
66°
38°
22
65°
40°
23
75°
39°
24
81°
45°
25
84°
46°
26
80°
51°
27
71°
51°
28
75°
52°
29
80°
55°
30
78°
50°
31
83°
50°
1
81°
53°
2
83°
53°
3
82°
49°
4
91°
55°
5
88°
59°
6
91°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Longmont
Longmont's May 2026 forecast shows daily high temperatures ranging from 78° to 91°, with overnight lows between 49° and 59°. The average high for May is 85° with an average low of 53°. 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 Longmont. See also: June | July | August.
