S
M
T
W
T
F
S
30
81°
65°
31
82°
57°
1
82°
55°
2
77°
56°
3
76°
60°
4
78°
65°
5
83°
56°
6
83°
55°
7
75°
54°
8
75°
61°
9
77°
61°
10
78°
59°
11
75°
60°
12
72°
58°
13
73°
53°
14
72°
51°
15
71°
52°
16
72°
56°
17
71°
58°
18
78°
59°
19
78°
59°
20
79°
58°
21
78°
55°
22
74°
56°
23
70°
50°
24
71°
49°
25
67°
49°
26
69°
48°
27
68°
48°
28
Hist. Avg.
72°
47°
29
Hist. Avg.
71°
47°
30
Hist. Avg.
71°
46°
1
Hist. Avg.
70°
46°
2
Hist. Avg.
70°
46°
3
Hist. Avg.
70°
45°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Oswego
Oswego's September 2026 forecast shows daily high temperatures ranging from 67° to 83°, with overnight lows between 48° and 65°. The average high for September is 75° with an average low of 56°. 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 Oswego. See also: October | November | December.
