S
M
T
W
T
F
S
30
88°
66°
31
84°
52°
1
77°
48°
2
85°
63°
3
96°
65°
4
90°
59°
5
92°
70°
6
83°
65°
7
77°
67°
8
86°
56°
9
78°
53°
10
88°
63°
11
88°
48°
12
75°
54°
13
63°
52°
14
64°
47°
15
68°
48°
16
67°
50°
17
71°
50°
18
69°
48°
19
68°
50°
20
71°
46°
21
74°
54°
22
76°
55°
23
76°
53°
24
75°
52°
25
72°
52°
26
71°
51°
27
74°
53°
28
75°
51°
29
70°
49°
30
60°
48°
1
59°
46°
2
58°
40°
3
58°
42°
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 58° to 88°, with overnight lows between 40° and 67°. The average high for September is 72° with an average low of 51°. 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.
