Average data for 10 years
1 September
Sunday
+26°
+21°
2 September
Monday
+26°
+20°
3 September
Tuesday
+24°
+20°
4 September
Wednesday
+25°
+19°
5 September
Thursday
+23°
+19°
6 September
Friday
+24°
+18°
7 September
Saturday
+25°
+19°
8 September
Sunday
+23°
+19°
9 September
Monday
+23°
+19°
10 September
today
+23°
+18°
11 September
tomorrow
+22°
+18°
12 September
Thursday
+22°
+17°
13 September
Friday
+23°
+17°
14 September
Saturday
+23°
+18°
15 September
Sunday
+21°
+18°
16 September
Monday
+20°
+16°
17 September
Tuesday
+21°
+15°
18 September
Wednesday
+22°
+17°
19 September
Thursday
+21°
+16°
20 September
Friday
+22°
+16°
21 September
Saturday
+23°
+18°
22 September
Sunday
+23°
+17°
23 September
Monday
+24°
+17°
24 September
Tuesday
+21°
+18°
25 September
Wednesday
+21°
+15°
26 September
Thursday
+21°
+16°
27 September
Friday
+22°
+18°
28 September
Saturday
+20°
+18°
29 September
Sunday
+19°
+16°
30 September
Monday
+17°
+13°
September in Allentown is the sunniest month of the year. In September, the weather in Allentown is typically warm. Average daily high temperature in September is about 22 degrees above zero. On average, Allentown has 18 sunny, 6 rainy, 5 partly cloudy, and 1 cloudy day in September. The rains are usually heavy. September as well as August is considered the most comfortable time to visit Allentown.