Click on a day for an hourly weather forecast
The temperatures in Bonn in September are comfortable with low of 11°C and and high up to 21°C.
You can expect about 3 to 8 days of rain in Bonn during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Bonn in September 2025.
If you’re planning to visit Bonn in the near future, we highly recommend that you review the 14 day weather forecast for Bonn before you arrive.
Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
---|---|---|---|---|---|---|---|
January | 5° / 0° | 8 | 15 | 8 | 65 mm | Awful | Bonn in January |
February | 6° / 1° | 8 | 14 | 6 | 52 mm | Awful | Bonn in February |
March | 11° / 3° | 6 | 23 | 2 | 56 mm | Bad | Bonn in March |
April | 16° / 6° | 4 | 25 | 1 | 47 mm | Good | Bonn in April |
May | 19° / 8° | 6 | 25 | 0 | 84 mm | Good | Bonn in May |
June | 22° / 12° | 6 | 24 | 0 | 91 mm | Good | Bonn in June |
July | 24° / 14° | 6 | 25 | 0 | 96 mm | Perfect | Bonn in July |
August | 24° / 14° | 5 | 26 | 0 | 78 mm | Perfect | Bonn in August |
September | 21° / 11° | 4 | 26 | 0 | 51 mm | Good | Bonn in September |
October | 15° / 7° | 5 | 26 | 0 | 56 mm | Good | Bonn in October |
November | 10° / 4° | 6 | 22 | 1 | 57 mm | Ok | Bonn in November |
December | 6° / 2° | 9 | 17 | 5 | 76 mm | Awful | Bonn in December |