S
M
T
W
T
F
S
30
95°
60°
31
94°
59°
1
86°
54°
2
85°
52°
3
86°
54°
4
86°
56°
5
91°
56°
6
91°
57°
7
94°
57°
8
98°
64°
9
102°
68°
10
105°
71°
11
98°
66°
12
94°
57°
13
83°
57°
14
85°
61°
15
87°
62°
16
93°
57°
17
93°
60°
18
92°
59°
19
93°
58°
20
92°
57°
21
92°
58°
22
93°
59°
23
95°
60°
24
91°
56°
25
83°
55°
26
89°
58°
27
90°
57°
28
86°
55°
29
88°
56°
30
90°
59°
1
91°
59°
2
90°
58°
3
90°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Three Rivers
Three Rivers's September 2026 forecast shows daily high temperatures ranging from 83° to 98°, with overnight lows between 55° and 66°. The average high for September is 90° with an average low of 58°. 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 Three Rivers. See also: October | November | December.