S
M
T
W
T
F
S
28
81°
69°
29
81°
69°
30
87°
72°
31
85°
71°
1
83°
74°
2
85°
72°
3
84°
71°
4
88°
73°
5
84°
74°
6
83°
74°
7
82°
70°
8
83°
72°
9
84°
72°
10
84°
73°
11
84°
74°
12
84°
73°
13
82°
72°
14
85°
71°
15
87°
73°
16
87°
75°
17
85°
75°
18
85°
74°
19
85°
74°
20
84°
73°
21
84°
74°
22
83°
74°
23
84°
73°
24
84°
73°
25
85°
73°
26
86°
72°
27
86°
72°
28
84°
70°
29
87°
75°
30
85°
72°
31
84°
73°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
January Weather in San Juan
San Juan's January 2026 forecast shows daily high temperatures ranging from ° to °, with overnight lows between ° and °. The average high for January is ° with an average low of °. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how January weather will actually feel in San Juan. See also: February | March | April.
