S
M
T
W
T
F
S
30
95°
70°
31
94°
68°
1
93°
63°
2
93°
61°
3
86°
62°
4
91°
69°
5
92°
70°
6
93°
68°
7
92°
68°
8
91°
69°
9
91°
68°
10
92°
65°
11
90°
62°
12
87°
62°
13
88°
65°
14
88°
65°
15
87°
64°
16
81°
65°
17
87°
57°
18
86°
54°
19
78°
54°
20
77°
56°
21
78°
59°
22
79°
62°
23
85°
62°
24
84°
63°
25
86°
57°
26
85°
58°
27
77°
53°
28
76°
52°
29
75°
53°
30
81°
60°
1
85°
60°
2
Hist. Avg.
76°
52°
3
Hist. Avg.
76°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Keystone Lake
Keystone Lake's September 2026 forecast shows daily high temperatures ranging from 75° to 95°, with overnight lows between 52° and 70°. The average high for September is 86° with an average low of 62°. 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 Keystone Lake. See also: October | November | December.
