S
M
T
W
T
F
S
26
60°
44°
27
68°
51°
28
64°
50°
29
57°
39°
30
56°
38°
1
50°
36°
2
56°
32°
3
67°
45°
4
81°
49°
5
60°
46°
6
58°
42°
7
61°
36°
8
65°
43°
9
76°
49°
10
62°
45°
11
56°
44°
12
74°
44°
13
59°
44°
14
65°
42°
15
76°
55°
16
83°
63°
17
87°
67°
18
80°
66°
19
79°
61°
20
61°
50°
21
61°
50°
22
67°
53°
23
70°
55°
24
74°
59°
25
85°
62°
26
87°
67°
27
87°
57°
28
75°
55°
29
74°
60°
30
74°
57°
31
74°
59°
1
75°
60°
2
77°
63°
3
80°
64°
4
79°
65°
5
81°
64°
6
78°
65°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Riverside
Riverside's May 2026 forecast shows daily high temperatures ranging from 74° to 87°, with overnight lows between 55° and 67°. The average high for May is 79° with an average low of 61°. 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 Riverside. See also: June | July | August.