S
M
T
W
T
F
S
30
74°
53°
31
76°
51°
1
78°
50°
2
74°
55°
3
66°
59°
4
79°
60°
5
71°
56°
6
68°
53°
7
78°
54°
8
77°
44°
9
67°
62°
10
82°
52°
11
73°
46°
12
76°
54°
13
77°
58°
14
76°
53°
15
70°
57°
16
74°
51°
17
71°
52°
18
67°
50°
19
65°
46°
20
67°
45°
21
66°
48°
22
63°
52°
23
68°
52°
24
72°
51°
25
69°
51°
26
70°
48°
27
64°
45°
28
67°
45°
29
70°
50°
30
71°
50°
1
71°
49°
2
69°
50°
3
67°
49°
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 63° to 82°, with overnight lows between 44° and 62°. The average high for September is 70° with an average low of 50°. 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.