S
M
T
W
T
F
S
30
78°
57°
31
79°
55°
1
81°
54°
2
77°
53°
3
76°
58°
4
80°
61°
5
83°
59°
6
83°
53°
7
76°
52°
8
75°
52°
9
78°
58°
10
75°
58°
11
77°
59°
12
74°
57°
13
75°
51°
14
73°
49°
15
71°
49°
16
72°
51°
17
73°
54°
18
77°
56°
19
80°
57°
20
81°
55°
21
77°
52°
22
78°
55°
23
74°
47°
24
79°
46°
25
69°
45°
26
69°
48°
27
77°
54°
28
77°
54°
29
Hist. Avg.
69°
47°
30
Hist. Avg.
69°
47°
1
Hist. Avg.
68°
47°
2
Hist. Avg.
68°
46°
3
Hist. Avg.
67°
46°
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 83°, with overnight lows between 45° and 61°. The average high for September is 76° with an average low of 54°. 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.
