S
M
T
W
T
F
S
30
75°
58°
31
68°
51°
1
76°
48°
2
83°
53°
3
78°
58°
4
81°
57°
5
83°
57°
6
78°
63°
7
73°
57°
8
66°
54°
9
74°
49°
10
80°
52°
11
60°
47°
12
58°
42°
13
65°
34°
14
54°
49°
15
59°
47°
16
58°
41°
17
67°
34°
18
74°
49°
19
70°
42°
20
63°
44°
21
70°
42°
22
72°
45°
23
67°
49°
24
81°
54°
25
78°
49°
26
66°
40°
27
63°
47°
28
68°
40°
29
75°
47°
30
64°
37°
1
66°
41°
2
65°
41°
3
59°
35°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Neptune
Neptune's September 2026 forecast shows daily high temperatures ranging from 59° to 75°, with overnight lows between 35° and 47°. The average high for September is 66° with an average low of 41°. 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 Neptune. See also: October | November | December.
