S
M
T
W
T
F
S
30
76°
54°
31
75°
53°
1
75°
54°
2
76°
58°
3
75°
58°
4
76°
60°
5
77°
60°
6
76°
61°
7
82°
60°
8
80°
59°
9
80°
59°
10
75°
58°
11
80°
59°
12
76°
58°
13
73°
58°
14
72°
57°
15
71°
56°
16
70°
56°
17
72°
55°
18
70°
56°
19
74°
55°
20
70°
54°
21
80°
54°
22
80°
48°
23
76°
43°
24
68°
45°
25
69°
52°
26
72°
51°
27
71°
53°
28
76°
51°
29
76°
48°
30
75°
50°
1
73°
51°
2
74°
49°
3
74°
48°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Lowell
Lowell's September 2026 forecast shows daily high temperatures ranging from 68° to 82°, with overnight lows between 43° and 61°. The average high for September is 75° with an average low of 54°. 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 Lowell. See also: October | November | December.