S
M
T
W
T
F
S
30
82°
48°
31
80°
44°
1
81°
54°
2
72°
41°
3
81°
38°
4
82°
40°
5
81°
38°
6
81°
39°
7
77°
40°
8
82°
47°
9
84°
50°
10
87°
51°
11
86°
50°
12
83°
40°
13
78°
44°
14
79°
46°
15
80°
46°
16
79°
44°
17
83°
46°
18
78°
44°
19
84°
47°
20
66°
44°
21
69°
48°
22
65°
44°
23
65°
42°
24
66°
45°
25
67°
45°
26
69°
47°
27
67°
46°
28
65°
43°
29
62°
34°
30
59°
34°
1
61°
41°
2
66°
42°
3
70°
43°
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 87°, with overnight lows between 34° and 51°. The average high for September is 74° with an average low of 44°. 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.
