S
M
T
W
T
F
S
30
75°
51°
31
75°
58°
1
76°
59°
2
78°
60°
3
78°
53°
4
76°
49°
5
74°
50°
6
73°
49°
7
73°
52°
8
77°
52°
9
78°
57°
10
80°
49°
11
74°
49°
12
72°
55°
13
72°
47°
14
73°
47°
15
68°
52°
16
71°
50°
17
70°
52°
18
73°
45°
19
71°
45°
20
69°
46°
21
72°
44°
22
69°
50°
23
72°
51°
24
75°
53°
25
76°
52°
26
75°
52°
27
74°
51°
28
76°
49°
29
73°
44°
30
70°
50°
1
72°
50°
2
74°
40°
3
72°
39°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Grass Lake
Grass Lake's September 2026 forecast shows daily high temperatures ranging from 68° to 80°, with overnight lows between 39° and 60°. The average high for September is 74° with an average low of 50°. 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 Grass Lake. See also: October | November | December.
