S
M
T
W
T
F
S
26
69°
55°
27
70°
55°
28
74°
51°
29
74°
53°
30
74°
59°
1
75°
60°
2
73°
59°
3
70°
58°
4
70°
56°
5
70°
56°
6
75°
55°
7
76°
57°
8
76°
61°
9
77°
61°
10
77°
61°
11
85°
58°
12
70°
59°
13
74°
60°
14
73°
59°
15
73°
61°
16
73°
61°
17
72°
59°
18
75°
61°
19
89°
56°
20
89°
57°
21
79°
61°
22
73°
61°
23
76°
62°
24
74°
57°
25
74°
58°
26
71°
60°
27
72°
56°
28
73°
56°
29
76°
61°
30
75°
60°
31
80°
62°
1
81°
63°
2
81°
64°
3
80°
62°
4
79°
62°
5
76°
63°
6
78°
62°
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 71° to 81°, with overnight lows between 56° and 64°. The average high for May is 76° with an average low of 60°. 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.
