S
M
T
W
T
F
S
30
89°
59°
31
81°
63°
1
81°
63°
2
88°
66°
3
89°
67°
4
89°
66°
5
88°
60°
6
86°
57°
7
79°
56°
8
79°
58°
9
81°
63°
10
82°
61°
11
78°
55°
12
76°
54°
13
77°
60°
14
78°
61°
15
82°
52°
16
84°
51°
17
74°
52°
18
74°
52°
19
75°
51°
20
73°
51°
21
73°
50°
22
74°
50°
23
74°
51°
24
77°
54°
25
78°
57°
26
80°
56°
27
80°
54°
28
73°
58°
29
79°
48°
30
80°
50°
1
72°
53°
2
71°
47°
3
69°
52°
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 69° to 89°, with overnight lows between 47° and 67°. The average high for September is 79° with an average low of 56°. 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.
