S
M
T
W
T
F
S
30
81°
58°
31
82°
58°
1
85°
57°
2
81°
58°
3
80°
62°
4
86°
61°
5
85°
63°
6
85°
62°
7
82°
56°
8
79°
56°
9
82°
61°
10
80°
61°
11
83°
62°
12
83°
61°
13
84°
55°
14
77°
53°
15
76°
53°
16
76°
54°
17
76°
55°
18
81°
58°
19
81°
58°
20
82°
59°
21
75°
57°
22
80°
56°
23
79°
58°
24
81°
51°
25
74°
49°
26
74°
54°
27
79°
55°
28
80°
56°
29
Hist. Avg.
73°
48°
30
Hist. Avg.
73°
48°
1
Hist. Avg.
72°
47°
2
Hist. Avg.
72°
47°
3
Hist. Avg.
72°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Hillsboro
Hillsboro's September 2026 forecast shows daily high temperatures ranging from 74° to 86°, with overnight lows between 49° and 63°. The average high for September is 80° with an average low of 57°. 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.
