S
M
T
W
T
F
S
30
83°
56°
31
82°
55°
1
76°
60°
2
76°
58°
3
79°
54°
4
81°
60°
5
82°
60°
6
82°
53°
7
80°
52°
8
74°
51°
9
74°
52°
10
80°
55°
11
80°
55°
12
79°
54°
13
73°
51°
14
72°
57°
15
77°
56°
16
79°
51°
17
78°
49°
18
70°
47°
19
69°
48°
20
70°
54°
21
69°
54°
22
70°
48°
23
69°
51°
24
68°
48°
25
69°
53°
26
73°
53°
27
75°
50°
28
75°
45°
29
68°
51°
30
68°
51°
1
67°
52°
2
68°
49°
3
69°
43°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Fairfield
Fairfield's September 2026 forecast shows daily high temperatures ranging from 67° to 83°, with overnight lows between 43° and 60°. The average high for September is 74° with an average low of 52°. 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 Fairfield. See also: October | November | December.