S
M
T
W
T
F
S
30
88°
71°
31
87°
70°
1
89°
71°
2
91°
70°
3
93°
71°
4
92°
70°
5
87°
68°
6
87°
68°
7
83°
68°
8
82°
68°
9
83°
67°
10
85°
65°
11
85°
66°
12
84°
66°
13
86°
65°
14
86°
66°
15
85°
66°
16
86°
65°
17
83°
66°
18
84°
66°
19
85°
65°
20
85°
66°
21
84°
66°
22
86°
65°
23
84°
65°
24
85°
64°
25
85°
64°
26
83°
63°
27
82°
63°
28
82°
62°
29
81°
61°
30
82°
61°
1
82°
60°
2
81°
61°
3
83°
61°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Duluth
Duluth's September 2026 forecast shows daily high temperatures ranging from 81° to 93°, with overnight lows between 60° and 71°. The average high for September is 85° with an average low of 66°. 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 Duluth. See also: October | November | December.
