The temperatures in Rio Negro in September are quite cold with temperatures between 8°C and 19°C, warm clothes are a must.
You can expect about 3 to 8 days of rain in Rio Negro 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 Rio Negro in September 2025.
If you’re planning to visit Rio Negro in the near future, we highly recommend that you review the 14 day weather forecast for Rio Negro before you arrive.
Temperatures
19° / 8°
Rainy Days
4
Snowy Days
0
Dry Days
26
Rainfall
81
mm
Sun Hours
10.2
Hrs
