S
M
T
W
T
F
S
26
91°
83°
27
89°
81°
28
N/A
29
88°
80°
30
86°
79°
1
88°
80°
2
88°
81°
3
86°
79°
4
87°
81°
5
90°
77°
6
91°
77°
7
90°
78°
8
94°
78°
9
92°
77°
10
93°
78°
11
88°
78°
12
89°
79°
13
89°
79°
14
90°
78°
15
89°
79°
16
89°
80°
17
90°
79°
18
89°
79°
19
89°
78°
20
90°
79°
21
89°
79°
22
89°
78°
23
90°
78°
24
89°
79°
25
89°
79°
26
90°
78°
27
89°
79°
28
89°
79°
29
90°
78°
30
89°
80°
31
89°
80°
1
90°
79°
2
89°
80°
3
89°
80°
4
90°
79°
5
89°
80°
6
89°
79°
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 86° to 94°, with overnight lows between 77° and 81°. The average high for May is 89° with an average low of 79°. 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.
