S
M
T
W
T
F
S
26
63°
42°
27
59°
43°
28
56°
37°
29
61°
33°
30
56°
37°
1
56°
32°
2
70°
47°
3
72°
46°
4
74°
41°
5
57°
37°
6
56°
37°
7
64°
37°
8
69°
44°
9
71°
45°
10
74°
47°
11
72°
47°
12
80°
53°
13
76°
51°
14
74°
47°
15
71°
48°
16
75°
54°
17
76°
53°
18
76°
53°
19
75°
51°
20
72°
48°
21
68°
47°
22
67°
45°
23
68°
46°
24
69°
46°
25
68°
47°
26
69°
46°
27
70°
47°
28
70°
49°
29
71°
57°
30
71°
53°
31
72°
50°
1
74°
55°
2
78°
59°
3
81°
60°
4
82°
61°
5
83°
61°
6
81°
60°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Sioux City
Sioux City's May 2026 forecast shows daily high temperatures ranging from 56° to 83°, with overnight lows between 37° and 61°. The average high for May is 72° with an average low of 49°. 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 Sioux City. See also: June | July | August.
