S
M
T
W
T
F
S
30
78°
60°
31
78°
60°
1
77°
61°
2
77°
57°
3
76°
50°
4
68°
48°
5
68°
57°
6
70°
59°
7
76°
58°
8
75°
57°
9
71°
50°
10
72°
57°
11
74°
56°
12
74°
58°
13
75°
58°
14
74°
57°
15
74°
52°
16
72°
51°
17
68°
53°
18
72°
48°
19
65°
46°
20
63°
44°
21
60°
43°
22
62°
53°
23
64°
50°
24
64°
44°
25
60°
43°
26
61°
51°
27
67°
52°
28
68°
47°
29
69°
45°
30
63°
46°
1
59°
47°
2
66°
42°
3
58°
42°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Oshawa
Oshawa's September 2026 forecast shows daily high temperatures ranging from 58° to 78°, with overnight lows between 42° and 61°. The average high for September is 69° with an average low of 51°. 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 Oshawa. See also: October | November | December.
