S
M
T
W
T
F
S
29
39°
32°
30
44°
27°
1
46°
24°
2
40°
19°
3
32°
20°
4
31°
25°
5
35°
25°
6
36°
21°
7
34°
25°
8
34°
22°
9
37°
19°
10
30°
19°
11
27°
17°
12
27°
16°
13
28°
14°
14
29°
12°
15
24°
15°
16
25°
20°
17
30°
13°
18
33°
7°
19
33°
14°
20
25°
12°
21
27°
10°
22
25°
6°
23
22°
8°
24
21°
18°
25
28°
13°
26
35°
4°
27
15°
4°
28
20°
15°
29
Hist. Avg.
31°
13°
30
Hist. Avg.
30°
13°
31
Hist. Avg.
30°
13°
1
Hist. Avg.
29°
12°
2
Hist. Avg.
29°
11°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
December Weather in Longueuil
Longueuil's December 2026 forecast shows daily high temperatures ranging from 15° to 46°, with overnight lows between 4° and 32°. The average high for December is 30° with an average low of 17°. 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 Longueuil. See also: January | February | March.