S
M
T
W
T
F
S
30
81°
70°
31
81°
71°
1
80°
71°
2
81°
70°
3
81°
71°
4
82°
71°
5
80°
70°
6
81°
71°
7
82°
71°
8
81°
70°
9
80°
71°
10
80°
71°
11
79°
70°
12
81°
70°
13
80°
71°
14
79°
71°
15
80°
70°
16
80°
71°
17
80°
71°
18
81°
70°
19
79°
70°
20
79°
69°
21
80°
70°
22
80°
70°
23
81°
69°
24
80°
71°
25
80°
71°
26
81°
70°
27
79°
69°
28
82°
67°
29
82°
68°
30
84°
70°
1
83°
69°
2
84°
70°
3
83°
69°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Mauna Kea
Mauna Kea's September 2026 forecast shows daily high temperatures ranging from 79° to 84°, with overnight lows between 67° and 71°. The average high for September is 81° with an average low of 70°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in Mauna Kea. See also: October | November | December.