S
M
T
W
T
F
S
30
104°
73°
31
103°
72°
1
102°
70°
2
101°
73°
3
99°
74°
4
99°
73°
5
102°
71°
6
100°
72°
7
102°
70°
8
103°
78°
9
100°
69°
10
88°
64°
11
92°
72°
12
89°
69°
13
96°
70°
14
96°
61°
15
77°
58°
16
80°
57°
17
80°
54°
18
78°
52°
19
74°
53°
20
76°
55°
21
80°
54°
22
85°
61°
23
86°
60°
24
84°
61°
25
79°
60°
26
82°
60°
27
80°
59°
28
81°
59°
29
78°
58°
30
79°
50°
1
70°
45°
2
69°
44°
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 68° to 103°, with overnight lows between 44° and 78°. The average high for September is 83° with an average low of 59°. 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.
