S
M
T
W
T
F
S
30
87°
66°
31
87°
65°
1
86°
65°
2
87°
64°
3
88°
65°
4
87°
65°
5
87°
66°
6
88°
67°
7
88°
66°
8
85°
66°
9
84°
65°
10
85°
65°
11
84°
66°
12
85°
66°
13
87°
67°
14
89°
67°
15
88°
66°
16
86°
65°
17
87°
64°
18
85°
66°
19
85°
66°
20
Hist. Avg.
87°
62°
21
Hist. Avg.
86°
61°
22
Hist. Avg.
86°
61°
23
Hist. Avg.
86°
61°
24
Hist. Avg.
86°
61°
25
Hist. Avg.
85°
61°
26
Hist. Avg.
85°
60°
27
Hist. Avg.
85°
60°
28
Hist. Avg.
85°
60°
29
Hist. Avg.
84°
60°
30
Hist. Avg.
84°
60°
1
Hist. Avg.
84°
59°
2
Hist. Avg.
84°
59°
3
Hist. Avg.
83°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in La Mesa
La Mesa's September 2026 forecast shows daily high temperatures ranging from 84° to 89°, with overnight lows between 64° and 67°. The average high for September is 86° with an average low of 66°. 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 La Mesa. See also: October | November | December.
