S
M
T
W
T
F
S
26
69°
52°
27
70°
53°
28
78°
48°
29
80°
51°
30
78°
53°
1
83°
56°
2
84°
56°
3
74°
58°
4
70°
55°
5
71°
54°
6
80°
49°
7
86°
56°
8
87°
56°
9
89°
57°
10
91°
58°
11
96°
59°
12
77°
60°
13
80°
60°
14
82°
55°
15
71°
57°
16
76°
57°
17
76°
54°
18
85°
55°
19
88°
57°
20
90°
59°
21
87°
57°
22
82°
59°
23
83°
57°
24
81°
58°
25
77°
57°
26
80°
57°
27
84°
58°
28
83°
56°
29
78°
52°
30
80°
54°
31
85°
58°
1
87°
60°
2
87°
61°
3
88°
61°
4
87°
54°
5
80°
55°
6
82°
55°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Rialto
Rialto's May 2026 forecast shows daily high temperatures ranging from 71° to 90°, with overnight lows between 52° and 61°. The average high for May is 82° with an average low of 57°. 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 Rialto. See also: June | July | August.
