S
M
T
W
T
F
S
26
75°
55°
27
75°
52°
28
59°
44°
29
62°
41°
30
66°
40°
1
65°
38°
2
63°
36°
3
83°
43°
4
85°
52°
5
60°
46°
6
57°
41°
7
70°
50°
8
76°
50°
9
76°
53°
10
72°
46°
11
72°
52°
12
74°
54°
13
79°
56°
14
77°
52°
15
76°
58°
16
81°
59°
17
74°
53°
18
77°
57°
19
75°
51°
20
72°
54°
21
72°
50°
22
68°
49°
23
69°
51°
24
70°
52°
25
69°
52°
26
70°
53°
27
72°
54°
28
71°
58°
29
73°
59°
30
74°
62°
31
73°
58°
1
74°
55°
2
75°
56°
3
78°
64°
4
77°
65°
5
79°
65°
6
79°
64°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Monticello
Monticello's May 2026 forecast shows daily high temperatures ranging from 57° to 85°, with overnight lows between 41° and 65°. The average high for May is 73° with an average low of 54°. 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 Monticello. See also: June | July | August.