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