S
M
T
W
T
F
S
26
69°
49°
27
71°
48°
28
70°
50°
29
71°
53°
30
72°
51°
31
74°
53°
1
73°
54°
2
74°
54°
3
74°
50°
4
75°
49°
5
73°
50°
6
71°
50°
7
70°
51°
8
73°
51°
9
74°
50°
10
74°
49°
11
71°
53°
12
73°
51°
13
72°
54°
14
72°
55°
15
75°
54°
16
74°
49°
17
75°
50°
18
71°
48°
19
73°
50°
20
71°
49°
21
70°
51°
22
71°
52°
23
72°
53°
24
73°
53°
25
71°
52°
26
73°
49°
27
74°
49°
28
71°
48°
29
68°
47°
30
66°
46°
31
66°
51°
1
73°
48°
2
73°
46°
3
69°
46°
4
65°
47°
5
67°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Riverhead
Riverhead's August 2026 forecast shows daily high temperatures ranging from 65° to 75°, with overnight lows between 46° and 55°. The average high for August is 72° with an average low of 50°. 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 Riverhead. See also: September | October | November.