S
M
T
W
T
F
S
30
65°
55°
31
66°
55°
1
66°
54°
2
64°
53°
3
66°
55°
4
67°
55°
5
66°
54°
6
67°
55°
7
66°
55°
8
66°
54°
9
66°
54°
10
66°
53°
11
62°
50°
12
61°
50°
13
60°
48°
14
60°
49°
15
63°
52°
16
64°
53°
17
62°
53°
18
60°
47°
19
61°
52°
20
66°
52°
21
61°
50°
22
61°
53°
23
63°
53°
24
67°
54°
25
68°
52°
26
67°
49°
27
62°
46°
28
59°
45°
29
59°
46°
30
60°
50°
1
61°
50°
2
63°
52°
3
62°
53°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Eureka
Eureka's September 2026 forecast shows daily high temperatures ranging from 59° to 68°, with overnight lows between 45° and 55°. The average high for September is 64° with an average low of 52°. 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 Eureka. See also: October | November | December.
