S
M
T
W
T
F
S
30
69°
52°
31
70°
54°
1
76°
54°
2
76°
51°
3
74°
46°
4
74°
51°
5
73°
47°
6
74°
45°
7
66°
49°
8
64°
51°
9
65°
47°
10
69°
42°
11
65°
51°
12
71°
43°
13
71°
46°
14
69°
42°
15
64°
49°
16
64°
41°
17
71°
40°
18
63°
42°
19
Hist. Avg.
68°
47°
20
Hist. Avg.
68°
46°
21
Hist. Avg.
68°
46°
22
Hist. Avg.
67°
46°
23
Hist. Avg.
67°
45°
24
Hist. Avg.
66°
45°
25
Hist. Avg.
66°
45°
26
Hist. Avg.
65°
44°
27
Hist. Avg.
65°
44°
28
Hist. Avg.
64°
43°
29
Hist. Avg.
64°
43°
30
Hist. Avg.
64°
43°
1
Hist. Avg.
63°
42°
2
Hist. Avg.
63°
42°
3
Hist. Avg.
62°
41°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Groton
Groton's September 2026 forecast shows daily high temperatures ranging from 63° to 76°, with overnight lows between 40° and 54°. The average high for September is 69° with an average low of 47°. 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.
