The average outside temperature in Rio de Janeiro in August for a typical day ranges from a high of 78°F (26°C) to a low of 63°F (17°C). Some would describe it as pleasantly warm with a gentle breeze.
The coldest month, August has days with highs of 78°F (26°C) and lows of 63°F (17°C). This average is based on historical data.
Average water temperature in Rio de Janeiro in August is 71,24º F (21.8°C), perfect for swimming. The warmest sea in August is 73,94º f (23.3°C), and the coldest is 68,54º F (20.3°C).