S
M
T
W
T
F
S
30
75°
49°
31
74°
49°
1
75°
50°
2
73°
49°
3
74°
56°
4
76°
52°
5
74°
52°
6
77°
51°
7
80°
54°
8
80°
58°
9
81°
57°
10
80°
47°
11
77°
45°
12
69°
45°
13
67°
46°
14
68°
44°
15
67°
42°
16
66°
43°
17
69°
44°
18
70°
48°
19
75°
43°
20
69°
43°
21
68°
42°
22
65°
41°
23
75°
52°
24
74°
48°
25
Hist. Avg.
71°
43°
26
Hist. Avg.
71°
42°
27
Hist. Avg.
70°
42°
28
Hist. Avg.
70°
42°
29
Hist. Avg.
69°
41°
30
Hist. Avg.
68°
41°
1
Hist. Avg.
68°
40°
2
Hist. Avg.
67°
40°
3
Hist. Avg.
67°
39°
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 65° to 81°, with overnight lows between 41° and 58°. The average high for September is 73° with an average low of 48°. 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.
