S
M
T
W
T
F
S
30
95°
65°
31
97°
64°
1
99°
71°
2
99°
73°
3
99°
74°
4
100°
72°
5
102°
73°
6
90°
74°
7
89°
62°
8
93°
59°
9
94°
69°
10
74°
66°
11
82°
68°
12
87°
69°
13
89°
68°
14
91°
68°
15
90°
68°
16
79°
66°
17
80°
61°
18
76°
56°
19
76°
56°
20
77°
56°
21
76°
55°
22
76°
56°
23
78°
54°
24
82°
60°
25
82°
60°
26
82°
59°
27
81°
59°
28
81°
58°
29
79°
59°
30
79°
57°
1
78°
52°
2
78°
58°
3
80°
58°
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 74° to 91°, with overnight lows between 52° and 69°. The average high for September is 81° with an average low of 60°. 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.
