S
M
T
W
T
F
S
26
82°
67°
27
81°
69°
28
83°
67°
29
86°
69°
30
95°
78°
1
89°
72°
2
88°
71°
3
87°
70°
4
88°
71°
5
88°
71°
6
87°
72°
7
88°
73°
8
88°
72°
9
89°
72°
10
89°
73°
11
86°
73°
12
88°
72°
13
84°
72°
14
88°
73°
15
90°
74°
16
89°
73°
17
90°
75°
18
92°
75°
19
90°
74°
20
90°
75°
21
92°
76°
22
91°
75°
23
91°
75°
24
90°
76°
25
91°
76°
26
91°
75°
27
90°
76°
28
91°
76°
29
91°
72°
30
89°
72°
31
88°
73°
1
87°
72°
2
88°
71°
3
91°
72°
4
92°
72°
5
92°
74°
6
91°
75°
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 81° to 95°, with overnight lows between 67° and 78°. The average high for May is 89° with an average low of 73°. 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.
