S
M
T
W
T
F
S
30
79°
53°
31
79°
54°
1
69°
61°
2
75°
61°
3
80°
60°
4
84°
59°
5
73°
54°
6
72°
51°
7
77°
56°
8
77°
52°
9
75°
60°
10
78°
56°
11
74°
52°
12
74°
54°
13
75°
55°
14
72°
53°
15
71°
50°
16
73°
55°
17
77°
52°
18
69°
47°
19
75°
53°
20
75°
51°
21
73°
50°
22
74°
51°
23
72°
52°
24
71°
49°
25
71°
49°
26
73°
52°
27
73°
52°
28
72°
48°
29
64°
44°
30
66°
46°
1
63°
43°
2
62°
44°
3
63°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Groton
Groton's September 2026 forecast shows daily high temperatures ranging from 62° to 84°, with overnight lows between 43° and 60°. The average high for September is 73° with an average low of 52°. 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 Groton. See also: October | November | December.
