S
M
T
W
T
F
S
30
85°
50°
31
78°
54°
1
71°
60°
2
78°
56°
3
77°
61°
4
85°
58°
5
73°
52°
6
69°
47°
7
80°
42°
8
81°
47°
9
80°
50°
10
86°
66°
11
78°
46°
12
78°
39°
13
69°
56°
14
74°
44°
15
70°
50°
16
76°
60°
17
78°
65°
18
79°
46°
19
68°
53°
20
67°
52°
21
68°
51°
22
67°
47°
23
64°
48°
24
68°
48°
25
70°
50°
26
68°
48°
27
67°
49°
28
69°
45°
29
74°
49°
30
66°
47°
1
65°
48°
2
65°
48°
3
72°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Holliston
Holliston's September 2026 forecast shows daily high temperatures ranging from 64° to 79°, with overnight lows between 45° and 65°. The average high for September is 70° with an average low of 50°. 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 Holliston. See also: October | November | December.
