S
M
T
W
T
F
S
26
79°
77°
27
80°
78°
28
81°
78°
29
80°
77°
30
80°
78°
1
80°
71°
2
73°
62°
3
75°
68°
4
77°
74°
5
79°
75°
6
87°
78°
7
81°
73°
8
80°
76°
9
86°
76°
10
86°
75°
11
83°
72°
12
82°
73°
13
84°
76°
14
83°
77°
15
87°
77°
16
84°
75°
17
88°
76°
18
84°
75°
19
87°
73°
20
86°
77°
21
89°
76°
22
89°
77°
23
88°
77°
24
89°
76°
25
88°
77°
26
88°
77°
27
85°
75°
28
85°
75°
29
86°
76°
30
85°
75°
31
85°
75°
1
86°
76°
2
85°
74°
3
85°
74°
4
86°
78°
5
88°
78°
6
89°
77°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Port Isabel
Port Isabel's May 2026 forecast shows daily high temperatures ranging from 80° to 89°, with overnight lows between 72° and 78°. The average high for May is 86° with an average low of 76°. 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 Port Isabel. See also: June | July | August.
