S
M
T
W
T
F
S
26
75°
55°
27
71°
51°
28
72°
55°
29
73°
57°
30
70°
54°
1
69°
52°
2
69°
52°
3
70°
53°
4
71°
54°
5
74°
56°
6
78°
57°
7
79°
60°
8
79°
60°
9
78°
59°
10
79°
60°
11
78°
58°
12
76°
56°
13
72°
54°
14
78°
59°
15
79°
60°
16
78°
57°
17
71°
55°
18
71°
55°
19
74°
57°
20
78°
60°
21
76°
58°
22
71°
56°
23
71°
56°
24
73°
60°
25
73°
55°
26
74°
55°
27
75°
57°
28
77°
60°
29
77°
61°
30
78°
62°
31
79°
62°
1
79°
64°
2
78°
63°
3
79°
63°
4
78°
62°
5
79°
63°
6
79°
63°
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 69° to 79°, with overnight lows between 51° and 64°. The average high for May is 75° with an average low of 58°. 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.
