S
M
T
W
T
F
S
30
94°
60°
31
95°
61°
1
94°
60°
2
93°
58°
3
93°
60°
4
91°
59°
5
85°
60°
6
90°
59°
7
93°
61°
8
90°
57°
9
85°
52°
10
79°
49°
11
78°
51°
12
79°
49°
13
77°
47°
14
74°
47°
15
75°
48°
16
76°
49°
17
77°
48°
18
79°
48°
19
76°
47°
20
76°
49°
21
78°
50°
22
75°
48°
23
81°
45°
24
Hist. Avg.
76°
50°
25
Hist. Avg.
75°
49°
26
Hist. Avg.
75°
49°
27
Hist. Avg.
74°
49°
28
Hist. Avg.
74°
48°
29
Hist. Avg.
73°
48°
30
Hist. Avg.
72°
48°
1
Hist. Avg.
72°
47°
2
Hist. Avg.
71°
47°
3
Hist. Avg.
71°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Lewiston
Lewiston's September 2026 forecast shows daily high temperatures ranging from 74° to 95°, with overnight lows between 45° and 61°. The average high for September is 83° with an average low of 53°. 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 Lewiston. See also: October | November | December.
