S
M
T
W
T
F
S
30
75°
45°
31
86°
51°
1
72°
57°
2
62°
53°
3
65°
51°
4
67°
49°
5
71°
52°
6
76°
52°
7
73°
53°
8
74°
52°
9
78°
54°
10
79°
53°
11
78°
53°
12
76°
54°
13
74°
50°
14
82°
49°
15
74°
48°
16
71°
48°
17
70°
47°
18
70°
44°
19
69°
49°
20
69°
45°
21
70°
42°
22
69°
43°
23
67°
42°
24
67°
41°
25
68°
42°
26
69°
42°
27
71°
49°
28
66°
47°
29
67°
42°
30
73°
47°
1
67°
46°
2
65°
43°
3
65°
42°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Hillsboro
Hillsboro's September 2026 forecast shows daily high temperatures ranging from 62° to 82°, with overnight lows between 41° and 57°. The average high for September is 71° with an average low of 48°. 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 Hillsboro. See also: October | November | December.
