S
M
T
W
T
F
S
30
82°
58°
31
82°
61°
1
79°
61°
2
82°
56°
3
81°
51°
4
74°
51°
5
73°
58°
6
76°
58°
7
80°
52°
8
74°
53°
9
72°
55°
10
73°
58°
11
75°
57°
12
80°
58°
13
79°
57°
14
80°
55°
15
79°
52°
16
73°
54°
17
71°
47°
18
73°
47°
19
69°
45°
20
68°
43°
21
66°
45°
22
67°
52°
23
68°
45°
24
70°
46°
25
71°
52°
26
71°
51°
27
73°
52°
28
74°
49°
29
73°
46°
30
69°
47°
1
67°
48°
2
72°
49°
3
65°
41°
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 65° to 82°, with overnight lows between 41° and 61°. 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 Three Rivers. See also: October | November | December.