S
M
T
W
T
F
S
26
74°
50°
27
66°
54°
28
70°
57°
29
64°
50°
30
63°
41°
1
57°
40°
2
55°
37°
3
63°
36°
4
77°
53°
5
68°
47°
6
57°
41°
7
61°
37°
8
70°
45°
9
76°
53°
10
71°
55°
11
71°
45°
12
79°
58°
13
71°
45°
14
68°
49°
15
73°
63°
16
83°
63°
17
87°
65°
18
87°
66°
19
77°
58°
20
75°
59°
21
80°
62°
22
81°
61°
23
80°
64°
24
81°
63°
25
82°
56°
26
82°
61°
27
82°
61°
28
83°
60°
29
84°
61°
30
84°
62°
31
83°
59°
1
78°
56°
2
81°
61°
3
85°
62°
4
85°
62°
5
81°
60°
6
82°
62°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Marengo
Marengo's May 2026 forecast shows daily high temperatures ranging from 68° to 87°, with overnight lows between 45° and 66°. The average high for May is 81° with an average low of 60°. 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 Marengo. See also: June | July | August.