S
M
T
W
T
F
S
30
76°
51°
31
72°
55°
1
73°
59°
2
76°
56°
3
75°
59°
4
76°
55°
5
80°
49°
6
80°
48°
7
89°
48°
8
95°
54°
9
102°
61°
10
102°
67°
11
94°
56°
12
93°
54°
13
80°
49°
14
83°
49°
15
82°
53°
16
72°
56°
17
74°
56°
18
80°
51°
19
80°
51°
20
80°
51°
21
69°
55°
22
71°
55°
23
89°
57°
24
N/A
25
77°
55°
26
90°
53°
27
74°
56°
28
77°
49°
29
86°
56°
30
89°
53°
1
86°
52°
2
84°
50°
3
98°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Napa
Napa's September 2026 forecast shows daily high temperatures ranging from ° to °, with overnight lows between ° and °. The average high for September is ° with an average low of °. 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 Napa. See also: October | November | December.
