S
M
T
W
T
F
S
30
87°
55°
31
84°
50°
1
74°
61°
2
93°
54°
3
88°
70°
4
97°
64°
5
93°
68°
6
95°
63°
7
91°
59°
8
82°
52°
9
81°
48°
10
88°
52°
11
79°
52°
12
68°
48°
13
77°
43°
14
72°
52°
15
66°
45°
16
79°
50°
17
73°
50°
18
75°
57°
19
64°
54°
20
59°
52°
21
64°
45°
22
73°
55°
23
77°
52°
24
76°
53°
25
77°
57°
26
75°
50°
27
74°
53°
28
66°
47°
29
64°
47°
30
65°
49°
1
66°
46°
2
65°
41°
3
66°
48°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Spearfish
Spearfish's September 2026 forecast shows daily high temperatures ranging from 64° to 77°, with overnight lows between 41° and 57°. The average high for September is 70° with an average low of 49°. 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 Spearfish. See also: October | November | December.
