S
M
T
W
T
F
S
29
40°
28°
30
39°
28°
1
38°
29°
2
41°
34°
3
45°
21°
4
52°
20°
5
44°
23°
6
31°
22°
7
33°
23°
8
34°
19°
9
34°
18°
10
32°
19°
11
29°
21°
12
31°
21°
13
34°
22°
14
31°
26°
15
32°
28°
16
35°
29°
17
36°
24°
18
35°
32°
19
38°
32°
20
37°
28°
21
37°
26°
22
35°
21°
23
32°
23°
24
33°
26°
25
35°
23°
26
34°
26°
27
30°
23°
28
32°
15°
29
34°
21°
30
33°
14°
31
32°
19°
1
28°
20°
2
Hist. Avg.
32°
20°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in St. Catharines
St. Catharines's December 2026 forecast shows daily high temperatures ranging from 28° to 52°, with overnight lows between 14° and 34°. The average high for December is 35° with an average low of 24°. 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 St. Catharines. See also: January | February | March.
