S
M
T
W
T
F
S
26
70°
35°
27
64°
37°
28
68°
35°
29
69°
40°
30
59°
33°
1
38°
31°
2
58°
35°
3
65°
43°
4
69°
45°
5
60°
36°
6
60°
28°
7
70°
43°
8
76°
46°
9
80°
50°
10
65°
39°
11
78°
50°
12
85°
49°
13
83°
54°
14
80°
51°
15
86°
54°
16
89°
57°
17
83°
51°
18
78°
39°
19
74°
46°
20
75°
48°
21
79°
49°
22
81°
50°
23
78°
49°
24
78°
48°
25
77°
47°
26
80°
48°
27
80°
49°
28
83°
51°
29
79°
51°
30
84°
54°
31
86°
54°
1
86°
55°
2
87°
55°
3
88°
56°
4
89°
57°
5
88°
56°
6
88°
57°
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 74° to 89°, with overnight lows between 39° and 57°. The average high for May is 82° with an average low of 51°. 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.
