S
M
T
W
T
F
S
29
54°
38°
30
55°
33°
1
54°
28°
2
41°
24°
3
45°
34°
4
54°
37°
5
50°
36°
6
40°
31°
7
40°
25°
8
38°
23°
9
39°
26°
10
43°
30°
11
45°
28°
12
50°
29°
13
46°
30°
14
42°
26°
15
44°
27°
16
44°
28°
17
40°
24°
18
40°
21°
19
39°
20°
20
37°
18°
21
35°
23°
22
38°
26°
23
40°
23°
24
38°
20°
25
37°
19°
26
36°
24°
27
38°
21°
28
37°
19°
29
36°
23°
30
36°
21°
31
37°
18°
1
36°
13°
2
34°
18°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Olean
Olean's December 2026 forecast shows daily high temperatures ranging from 34° to 55°, with overnight lows between 13° and 38°. The average high for December is 42° with an average low of 25°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how December weather will actually feel in Olean. See also: January | February | March.
