S
M
T
W
T
F
S
28
56°
27°
29
54°
24°
30
56°
33°
31
51°
28°
1
43°
22°
2
56°
33°
3
57°
40°
4
50°
39°
5
44°
41°
6
42°
37°
7
43°
26°
8
42°
24°
9
57°
36°
10
56°
30°
11
54°
24°
12
46°
23°
13
48°
40°
14
56°
43°
15
55°
47°
16
60°
38°
17
61°
35°
18
60°
37°
19
54°
48°
20
54°
45°
21
50°
36°
22
54°
28°
23
46°
34°
24
54°
44°
25
53°
43°
26
56°
38°
27
53°
31°
28
54°
45°
29
52°
42°
30
51°
38°
31
57°
42°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
January Weather in Siena
Siena'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 Siena. See also: February | March | April.
