S
M
T
W
T
F
S
30
71°
52°
31
73°
57°
1
74°
54°
2
71°
52°
3
70°
51°
4
70°
50°
5
71°
56°
6
71°
56°
7
73°
55°
8
73°
56°
9
69°
54°
10
Hist. Avg.
73°
51°
11
Hist. Avg.
73°
51°
12
Hist. Avg.
73°
51°
13
Hist. Avg.
72°
50°
14
Hist. Avg.
72°
50°
15
Hist. Avg.
72°
50°
16
Hist. Avg.
71°
49°
17
Hist. Avg.
71°
49°
18
Hist. Avg.
71°
49°
19
Hist. Avg.
70°
48°
20
Hist. Avg.
70°
48°
21
Hist. Avg.
70°
47°
22
Hist. Avg.
69°
47°
23
Hist. Avg.
69°
47°
24
Hist. Avg.
69°
46°
25
Hist. Avg.
68°
46°
26
Hist. Avg.
68°
46°
27
Hist. Avg.
68°
45°
28
Hist. Avg.
67°
45°
29
Hist. Avg.
67°
45°
30
Hist. Avg.
67°
44°
1
Hist. Avg.
66°
44°
2
Hist. Avg.
66°
43°
3
Hist. Avg.
65°
43°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Cornwall
Cornwall's September 2026 forecast shows daily high temperatures ranging from 69° to 74°, with overnight lows between 50° and 57°. The average high for September is 71° 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 Cornwall. See also: October | November | December.
