S
M
T
W
T
F
S
30
80°
60°
31
80°
60°
1
79°
59°
2
81°
59°
3
78°
58°
4
75°
58°
5
74°
56°
6
75°
56°
7
77°
58°
8
79°
58°
9
79°
57°
10
78°
58°
11
77°
58°
12
75°
57°
13
76°
57°
14
70°
54°
15
71°
51°
16
71°
55°
17
74°
54°
18
77°
52°
19
75°
51°
20
75°
50°
21
76°
51°
22
72°
49°
23
71°
49°
24
72°
51°
25
73°
55°
26
74°
55°
27
75°
54°
28
76°
54°
29
74°
51°
30
71°
46°
1
69°
46°
2
64°
45°
3
62°
42°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Lake Arrowhead
Lake Arrowhead's September 2026 forecast shows daily high temperatures ranging from 62° to 81°, with overnight lows between 42° and 60°. The average high for September is 74° with an average low of 54°. 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 Lake Arrowhead. See also: October | November | December.
