S
M
T
W
T
F
S
30
65°
56°
31
65°
57°
1
69°
61°
2
70°
61°
3
68°
57°
4
69°
56°
5
69°
57°
6
69°
57°
7
73°
60°
8
74°
60°
9
71°
61°
10
72°
58°
11
70°
59°
12
71°
60°
13
69°
59°
14
72°
58°
15
73°
59°
16
70°
57°
17
73°
58°
18
68°
59°
19
73°
59°
20
74°
58°
21
74°
59°
22
73°
58°
23
69°
59°
24
71°
58°
25
74°
59°
26
76°
60°
27
76°
61°
28
75°
60°
29
75°
60°
30
74°
59°
1
75°
60°
2
73°
59°
3
69°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Union Square
Union Square's September 2026 forecast shows daily high temperatures ranging from 68° to 76°, with overnight lows between 56° and 61°. The average high for September is 72° with an average low of 59°. 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 Union Square. See also: October | November | December.
