S
M
T
W
T
F
S
30
80°
53°
31
82°
53°
1
82°
52°
2
84°
54°
3
85°
54°
4
84°
53°
5
84°
53°
6
83°
52°
7
83°
52°
8
78°
49°
9
82°
51°
10
80°
51°
11
79°
47°
12
77°
49°
13
82°
48°
14
83°
51°
15
82°
47°
16
71°
46°
17
78°
49°
18
80°
50°
19
81°
50°
20
81°
49°
21
79°
48°
22
75°
51°
23
79°
49°
24
72°
46°
25
67°
40°
26
65°
42°
27
71°
45°
28
73°
45°
29
73°
44°
30
72°
36°
1
63°
36°
2
59°
41°
3
68°
44°
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 85°, with overnight lows between 36° and 54°. The average high for September is 77° with an average low of 48°. 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.
