S
M
T
W
T
F
S
30
63°
53°
31
65°
55°
1
69°
55°
2
65°
56°
3
67°
55°
4
69°
52°
5
63°
51°
6
66°
51°
7
66°
53°
8
71°
49°
9
74°
52°
10
61°
54°
11
64°
52°
12
68°
49°
13
68°
50°
14
66°
52°
15
63°
51°
16
63°
56°
17
68°
56°
18
62°
57°
19
60°
54°
20
58°
53°
21
60°
52°
22
65°
53°
23
62°
49°
24
65°
56°
25
65°
48°
26
63°
50°
27
62°
48°
28
60°
48°
29
63°
50°
30
61°
49°
1
62°
50°
2
59°
47°
3
59°
47°
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 65°, with overnight lows between 47° and 56°. The average high for September is 62° with an average low of 49°. 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.
