S
M
T
W
T
F
S
29
51°
29°
30
49°
23°
1
43°
23°
2
37°
21°
3
36°
20°
4
33°
32°
5
38°
26°
6
41°
22°
7
35°
22°
8
34°
26°
9
34°
26°
10
33°
28°
11
37°
25°
12
38°
22°
13
35°
20°
14
34°
21°
15
32°
21°
16
32°
19°
17
30°
27°
18
Hist. Avg.
34°
23°
19
Hist. Avg.
34°
22°
20
Hist. Avg.
34°
22°
21
Hist. Avg.
34°
22°
22
Hist. Avg.
34°
22°
23
Hist. Avg.
34°
22°
24
Hist. Avg.
33°
22°
25
Hist. Avg.
33°
21°
26
Hist. Avg.
33°
21°
27
Hist. Avg.
33°
21°
28
Hist. Avg.
33°
21°
29
Hist. Avg.
33°
21°
30
Hist. Avg.
33°
21°
31
Hist. Avg.
33°
20°
1
Hist. Avg.
33°
20°
2
Hist. Avg.
32°
20°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
December Weather in St. Catharines
St. Catharines's December 2026 forecast shows daily high temperatures ranging from 30° to 51°, with overnight lows between 19° and 32°. The average high for December is 37° 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.
