S
M
T
W
T
F
S
30
89°
63°
31
90°
67°
1
91°
70°
2
95°
71°
3
96°
69°
4
90°
68°
5
86°
64°
6
82°
60°
7
81°
60°
8
80°
59°
9
81°
58°
10
82°
62°
11
80°
55°
12
79°
55°
13
79°
56°
14
78°
54°
15
80°
59°
16
78°
59°
17
81°
58°
18
80°
57°
19
81°
58°
20
81°
58°
21
80°
57°
22
81°
57°
23
81°
56°
24
80°
57°
25
81°
56°
26
79°
55°
27
80°
56°
28
79°
55°
29
80°
54°
30
78°
53°
1
78°
53°
2
77°
52°
3
78°
53°
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 77° to 96°, with overnight lows between 52° and 71°. The average high for September is 82° 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 Hillsboro. See also: October | November | December.
