S
M
T
W
T
F
S
30
82°
57°
31
78°
55°
1
76°
58°
2
75°
57°
3
77°
57°
4
76°
56°
5
74°
56°
6
74°
60°
7
75°
56°
8
75°
55°
9
76°
55°
10
74°
56°
11
73°
54°
12
72°
54°
13
74°
56°
14
73°
56°
15
76°
59°
16
79°
58°
17
80°
59°
18
79°
56°
19
71°
54°
20
78°
57°
21
69°
47°
22
69°
48°
23
Hist. Avg.
74°
49°
24
Hist. Avg.
74°
49°
25
Hist. Avg.
73°
48°
26
Hist. Avg.
73°
48°
27
Hist. Avg.
72°
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 69° to 82°, with overnight lows between 47° and 60°. 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.
