S
M
T
W
T
F
S
29
32°
17°
30
31°
17°
1
34°
19°
2
35°
21°
3
36°
28°
4
37°
29°
5
43°
26°
6
38°
24°
7
39°
22°
8
38°
26°
9
41°
27°
10
42°
19°
11
35°
17°
12
Hist. Avg.
40°
25°
13
Hist. Avg.
40°
25°
14
Hist. Avg.
39°
25°
15
Hist. Avg.
39°
24°
16
Hist. Avg.
39°
24°
17
Hist. Avg.
39°
24°
18
Hist. Avg.
39°
24°
19
Hist. Avg.
38°
24°
20
Hist. Avg.
38°
24°
21
Hist. Avg.
38°
24°
22
Hist. Avg.
38°
24°
23
Hist. Avg.
38°
24°
24
Hist. Avg.
38°
24°
25
Hist. Avg.
38°
24°
26
Hist. Avg.
37°
24°
27
Hist. Avg.
37°
24°
28
Hist. Avg.
37°
24°
29
Hist. Avg.
37°
24°
30
Hist. Avg.
37°
24°
31
Hist. Avg.
37°
24°
1
Hist. Avg.
0°
0°
2
Hist. Avg.
38°
24°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
December Weather in Ontario
Ontario's December 2026 forecast shows daily high temperatures ranging from 31° to 43°, with overnight lows between 17° and 29°. The average high for December is 37° with an average low of 22°. 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 Ontario. See also: January | February | March.
