S
M
T
W
T
F
S
30
35°
28°
31
36°
27°
1
35°
26°
2
29°
25°
3
28°
25°
4
30°
24°
5
30°
23°
6
26°
22°
7
30°
20°
8
31°
19°
9
27°
16°
10
21°
17°
11
27°
21°
12
28°
20°
13
26°
13°
14
14°
4°
15
19°
3°
16
15°
11°
17
17°
10°
18
19°
7°
19
17°
8°
20
15°
3°
21
18°
3°
22
18°
6°
23
20°
10°
24
18°
10°
25
19°
9°
26
19°
8°
27
17°
8°
28
14°
9°
29
19°
9°
30
19°
10°
1
20°
9°
2
19°
8°
3
19°
7°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Alert
Alert's September 2026 forecast shows daily high temperatures ranging from 14° to 36°, with overnight lows between 3° and 28°. The average high for September is 23° with an average low of 14°. 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 Alert. See also: October | November | December.