S
M
T
W
T
F
S
30
76°
57°
31
81°
57°
1
82°
56°
2
82°
53°
3
78°
51°
4
74°
56°
5
74°
56°
6
82°
50°
7
75°
47°
8
72°
47°
9
71°
53°
10
72°
55°
11
75°
54°
12
79°
54°
13
80°
46°
14
75°
45°
15
69°
45°
16
69°
49°
17
70°
44°
18
68°
43°
19
70°
40°
20
68°
42°
21
67°
49°
22
68°
46°
23
75°
49°
24
74°
50°
25
75°
50°
26
74°
48°
27
75°
49°
28
74°
45°
29
72°
44°
30
65°
46°
1
70°
44°
2
73°
48°
3
64°
37°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Winthrop
Winthrop's September 2026 forecast shows daily high temperatures ranging from 64° to 82°, with overnight lows between 37° and 57°. The average high for September is 73° with an average low of 49°. 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 Winthrop. See also: October | November | December.
