S
M
T
W
T
F
S
30
83°
60°
31
82°
48°
1
81°
48°
2
70°
46°
3
68°
47°
4
68°
49°
5
69°
49°
6
74°
57°
7
79°
52°
8
80°
46°
9
74°
49°
10
72°
46°
11
69°
55°
12
73°
46°
13
70°
43°
14
65°
47°
15
68°
55°
16
73°
49°
17
70°
45°
18
66°
52°
19
72°
44°
20
71°
40°
21
64°
44°
22
62°
55°
23
73°
44°
24
74°
44°
25
71°
50°
26
62°
51°
27
65°
48°
28
69°
52°
29
68°
52°
30
70°
44°
1
71°
39°
2
66°
38°
3
56°
39°
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 56° to 83°, with overnight lows between 38° and 60°. 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.
