S
M
T
W
T
F
S
30
78°
61°
31
79°
59°
1
73°
56°
2
79°
62°
3
84°
56°
4
79°
54°
5
76°
50°
6
76°
57°
7
79°
56°
8
79°
47°
9
74°
47°
10
68°
45°
11
68°
47°
12
70°
47°
13
69°
45°
14
67°
43°
15
64°
42°
16
64°
43°
17
65°
43°
18
65°
44°
19
66°
44°
20
65°
45°
21
70°
51°
22
74°
52°
23
74°
44°
24
72°
53°
25
68°
46°
26
70°
40°
27
61°
50°
28
64°
48°
29
60°
45°
30
61°
46°
1
62°
39°
2
59°
46°
3
58°
45°
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 58° to 84°, with overnight lows between 39° and 62°. The average high for September is 70° with an average low of 49°. 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.
