S
M
T
W
T
F
S
26
87°
79°
27
87°
79°
28
86°
78°
29
87°
79°
30
87°
79°
31
88°
78°
1
88°
79°
2
88°
79°
3
88°
78°
4
88°
79°
5
87°
79°
6
87°
78°
7
88°
79°
8
88°
79°
9
89°
78°
10
90°
76°
11
91°
76°
12
92°
77°
13
92°
75°
14
90°
75°
15
92°
77°
16
90°
77°
17
90°
76°
18
91°
76°
19
90°
77°
20
90°
76°
21
89°
77°
22
89°
77°
23
90°
76°
24
89°
77°
25
90°
76°
26
89°
77°
27
89°
77°
28
91°
76°
29
89°
77°
30
89°
77°
31
90°
76°
1
89°
77°
2
89°
77°
3
90°
76°
4
90°
77°
5
89°
76°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in San Juan
San Juan's August 2026 forecast shows daily high temperatures ranging from 86° to 92°, with overnight lows between 75° and 79°. The average high for August is 89° 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 August weather will actually feel in San Juan. See also: September | October | November.
