S
M
T
W
T
F
S
30
82°
57°
31
83°
56°
1
82°
57°
2
86°
57°
3
87°
56°
4
83°
54°
5
82°
52°
6
83°
51°
7
82°
52°
8
84°
55°
9
83°
51°
10
84°
52°
11
86°
52°
12
82°
50°
13
Hist. Avg.
85°
54°
14
Hist. Avg.
85°
54°
15
Hist. Avg.
85°
54°
16
Hist. Avg.
85°
53°
17
Hist. Avg.
85°
53°
18
Hist. Avg.
84°
53°
19
Hist. Avg.
84°
53°
20
Hist. Avg.
84°
53°
21
Hist. Avg.
84°
53°
22
Hist. Avg.
84°
53°
23
Hist. Avg.
84°
53°
24
Hist. Avg.
84°
53°
25
Hist. Avg.
84°
52°
26
Hist. Avg.
83°
52°
27
Hist. Avg.
83°
52°
28
Hist. Avg.
83°
52°
29
Hist. Avg.
83°
52°
30
Hist. Avg.
83°
52°
1
Hist. Avg.
82°
52°
2
Hist. Avg.
82°
52°
3
Hist. Avg.
82°
51°
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 82° to 87°, with overnight lows between 50° and 57°. The average high for September is 84° 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 September weather will actually feel in Napa. See also: October | November | December.
