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