S
M
T
W
T
F
S
30
102°
76°
31
103°
81°
1
105°
82°
2
107°
81°
3
106°
81°
4
107°
80°
5
107°
80°
6
106°
79°
7
103°
78°
8
100°
77°
9
100°
74°
10
99°
75°
11
98°
77°
12
99°
79°
13
100°
78°
14
99°
76°
15
100°
73°
16
98°
72°
17
Hist. Avg.
101°
77°
18
Hist. Avg.
101°
77°
19
Hist. Avg.
100°
77°
20
Hist. Avg.
100°
76°
21
Hist. Avg.
100°
76°
22
Hist. Avg.
99°
76°
23
Hist. Avg.
99°
75°
24
Hist. Avg.
99°
75°
25
Hist. Avg.
98°
74°
26
Hist. Avg.
98°
74°
27
Hist. Avg.
98°
74°
28
Hist. Avg.
97°
73°
29
Hist. Avg.
97°
73°
30
Hist. Avg.
96°
72°
1
Hist. Avg.
96°
72°
2
Hist. Avg.
96°
71°
3
Hist. Avg.
95°
71°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in San Luis
San Luis's September 2026 forecast shows daily high temperatures ranging from 98° to 107°, with overnight lows between 72° and 82°. The average high for September is 102° with an average low of 78°. 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 San Luis. See also: October | November | December.
