S
M
T
W
T
F
S
30
86°
47°
31
82°
43°
1
74°
50°
2
73°
54°
3
82°
46°
4
81°
41°
5
72°
43°
6
71°
51°
7
78°
48°
8
81°
41°
9
70°
41°
10
68°
43°
11
66°
41°
12
67°
39°
13
67°
44°
14
68°
46°
15
67°
49°
16
73°
48°
17
78°
41°
18
70°
41°
19
64°
46°
20
70°
38°
21
69°
41°
22
65°
37°
23
62°
36°
24
63°
36°
25
67°
43°
26
61°
32°
27
61°
33°
28
Hist. Avg.
65°
36°
29
Hist. Avg.
65°
36°
30
Hist. Avg.
64°
36°
1
Hist. Avg.
64°
35°
2
Hist. Avg.
63°
35°
3
Hist. Avg.
63°
34°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Glen Ullin
Glen Ullin's September 2026 forecast shows daily high temperatures ranging from 61° to 86°, with overnight lows between 32° and 54°. The average high for September is 71° with an average low of 43°. 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 Glen Ullin. See also: October | November | December.