S
M
T
W
T
F
S
26
74°
53°
27
81°
50°
28
71°
51°
29
78°
47°
30
81°
47°
31
89°
46°
1
70°
49°
2
71°
46°
3
79°
41°
4
90°
44°
5
94°
48°
6
94°
51°
7
88°
50°
8
86°
48°
9
82°
50°
10
79°
50°
11
81°
49°
12
72°
54°
13
81°
54°
14
80°
56°
15
70°
56°
16
79°
53°
17
82°
53°
18
82°
53°
19
87°
53°
20
91°
50°
21
79°
54°
22
72°
55°
23
77°
52°
24
92°
47°
25
84°
52°
26
73°
57°
27
70°
56°
28
71°
56°
29
70°
53°
30
74°
54°
31
72°
52°
1
70°
52°
2
66°
50°
3
70°
51°
4
76°
52°
5
73°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Cathlamet
Cathlamet's August 2026 forecast shows daily high temperatures ranging from 66° to 76°, with overnight lows between 50° and 57°. The average high for August is 71° with an average low of 53°. 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 Cathlamet. See also: September | October | November.