S
M
T
W
T
F
S
26
90°
61°
27
81°
60°
28
87°
61°
29
88°
62°
30
89°
63°
31
90°
63°
1
88°
61°
2
89°
61°
3
87°
60°
4
86°
61°
5
81°
60°
6
78°
60°
7
82°
59°
8
83°
60°
9
87°
61°
10
83°
59°
11
79°
53°
12
80°
51°
13
79°
56°
14
85°
57°
15
88°
49°
16
79°
49°
17
78°
45°
18
75°
47°
19
77°
48°
20
78°
53°
21
81°
54°
22
82°
57°
23
86°
54°
24
87°
45°
25
77°
44°
26
73°
44°
27
75°
51°
28
83°
55°
29
85°
56°
30
86°
47°
31
82°
43°
1
74°
50°
2
73°
54°
3
82°
46°
4
81°
41°
5
72°
43°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Glen Ullin
Glen Ullin's August 2026 forecast shows daily high temperatures ranging from 72° to 90°, with overnight lows between 41° and 63°. The average high for August is 82° 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 August weather will actually feel in Glen Ullin. See also: September | October | November.