S
M
T
W
T
F
S
26
69°
53°
27
68°
51°
28
69°
51°
29
69°
52°
30
70°
51°
1
70°
52°
2
74°
55°
3
75°
56°
4
70°
53°
5
71°
52°
6
70°
54°
7
71°
53°
8
71°
53°
9
72°
54°
10
75°
55°
11
75°
55°
12
76°
54°
13
72°
53°
14
70°
54°
15
71°
54°
16
74°
55°
17
78°
60°
18
79°
62°
19
79°
62°
20
78°
61°
21
78°
62°
22
75°
61°
23
78°
60°
24
80°
60°
25
76°
62°
26
80°
63°
27
81°
62°
28
81°
61°
29
80°
61°
30
80°
60°
31
79°
61°
1
80°
62°
2
80°
60°
3
79°
60°
4
75°
57°
5
74°
57°
6
73°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Fullerton
Fullerton's May 2026 forecast shows daily high temperatures ranging from 68° to 81°, with overnight lows between 51° and 63°. The average high for May is 75° 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 Fullerton. See also: June | July | August.
