S
M
T
W
T
F
S
30
92°
66°
31
92°
65°
1
91°
59°
2
86°
57°
3
82°
60°
4
89°
66°
5
91°
65°
6
92°
64°
7
91°
63°
8
89°
62°
9
88°
61°
10
88°
55°
11
79°
56°
12
80°
58°
13
84°
61°
14
86°
61°
15
86°
60°
16
81°
61°
17
82°
51°
18
82°
49°
19
75°
50°
20
75°
51°
21
77°
57°
22
80°
59°
23
82°
60°
24
83°
58°
25
84°
48°
26
82°
49°
27
73°
47°
28
72°
48°
29
72°
48°
30
72°
57°
1
71°
50°
2
Hist. Avg.
75°
51°
3
Hist. Avg.
74°
50°
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 71° to 92°, with overnight lows between 47° and 66°. The average high for September is 83° with an average low of 57°. 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.
