S
M
T
W
T
F
S
26
91°
81°
27
92°
80°
28
93°
80°
29
94°
80°
30
91°
81°
31
91°
80°
1
93°
79°
2
91°
81°
3
91°
81°
4
91°
80°
5
93°
79°
6
92°
80°
7
91°
79°
8
91°
80°
9
90°
80°
10
91°
82°
11
88°
77°
12
86°
81°
13
92°
81°
14
91°
82°
15
91°
83°
16
90°
81°
17
90°
81°
18
91°
80°
19
90°
81°
20
91°
80°
21
90°
80°
22
90°
81°
23
91°
80°
24
91°
80°
25
90°
79°
26
91°
80°
27
90°
79°
28
89°
79°
29
90°
80°
30
89°
78°
31
88°
76°
1
88°
75°
2
89°
76°
3
88°
79°
4
89°
78°
5
87°
78°
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 87° to 91°, with overnight lows between 75° and 80°. The average high for August is 89° with an average low of 78°. 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.
