Most of the month of September is hot, with the last couple of weeks cooling down. The maximum temperature stays above 30 °C (86 °F) and the average temperature is about 26 °C (79 °F). Summer clothing is enough.
The sun is shining and the ultraviolet radiation is not weak, so wear sunscreen with SPF 12-15 and PA+ to protect your skin. September falls during the low travel season.