S
M
T
W
T
F
S
26
92°
76°
27
86°
77°
28
88°
76°
29
85°
75°
30
89°
76°
1
87°
76°
2
90°
76°
3
90°
76°
4
91°
77°
5
92°
77°
6
92°
77°
7
88°
77°
8
87°
76°
9
87°
76°
10
89°
77°
11
88°
77°
12
88°
76°
13
87°
76°
14
92°
75°
15
90°
77°
16
88°
78°
17
90°
78°
18
87°
77°
19
88°
76°
20
88°
76°
21
89°
76°
22
88°
75°
23
87°
74°
24
87°
75°
25
86°
74°
26
86°
75°
27
86°
74°
28
87°
75°
29
88°
75°
30
89°
76°
31
92°
78°
1
93°
76°
2
89°
77°
3
87°
77°
4
88°
77°
5
87°
78°
6
88°
78°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in San Juan
San Juan's May 2026 forecast shows daily high temperatures ranging from 87° to 89°, with overnight lows between 77° and 78°. The average high for May is 88° with an average low of 77°. 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 San Juan. See also: June | July | August.
