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