S
M
T
W
T
F
S
30
76°
51°
31
86°
46°
1
84°
61°
2
77°
57°
3
72°
48°
4
61°
46°
5
75°
46°
6
75°
52°
7
70°
46°
8
75°
45°
9
82°
45°
10
88°
50°
11
81°
55°
12
90°
52°
13
75°
55°
14
69°
43°
15
77°
49°
16
81°
54°
17
83°
53°
18
75°
51°
19
81°
46°
20
86°
49°
21
83°
53°
22
78°
47°
23
78°
51°
24
79°
50°
25
78°
48°
26
77°
51°
27
76°
43°
28
68°
39°
29
68°
42°
30
71°
44°
1
68°
42°
2
73°
44°
3
66°
36°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Nampa
Nampa's September 2026 forecast shows daily high temperatures ranging from 66° to 86°, with overnight lows between 36° and 54°. The average high for September is 76° with an average low of 47°. 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 Nampa. See also: October | November | December.
