S
M
T
W
T
F
S
30
76°
59°
31
77°
58°
1
76°
55°
2
70°
51°
3
69°
50°
4
69°
50°
5
71°
51°
6
75°
57°
7
77°
58°
8
77°
57°
9
76°
57°
10
77°
56°
11
76°
56°
12
77°
57°
13
77°
58°
14
77°
51°
15
65°
49°
16
64°
50°
17
67°
49°
18
64°
48°
19
65°
44°
20
64°
46°
21
73°
49°
22
73°
50°
23
72°
43°
24
70°
43°
25
65°
44°
26
67°
50°
27
69°
51°
28
70°
49°
29
63°
40°
30
61°
40°
1
61°
46°
2
66°
42°
3
69°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in McHenry
McHenry's September 2026 forecast shows daily high temperatures ranging from 61° to 77°, with overnight lows between 40° and 59°. The average high for September is 70° 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 McHenry. See also: October | November | December.
