S
M
T
W
T
F
S
30
79°
67°
31
81°
66°
1
79°
68°
2
83°
65°
3
78°
63°
4
77°
63°
5
76°
62°
6
78°
61°
7
76°
61°
8
78°
62°
9
79°
59°
10
74°
63°
11
71°
59°
12
71°
58°
13
72°
58°
14
75°
62°
15
77°
62°
16
77°
61°
17
76°
61°
18
76°
62°
19
75°
62°
20
72°
61°
21
76°
61°
22
76°
60°
23
75°
61°
24
74°
59°
25
70°
57°
26
66°
53°
27
66°
54°
28
70°
57°
29
73°
58°
30
73°
57°
1
72°
57°
2
71°
56°
3
72°
57°
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 66° to 83°, with overnight lows between 53° and 68°. The average high for September is 75° with an average low of 60°. 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.
