I'll be in Macau, last week of September. Do you advise me to bring sweaters already? Thanks

The local autumn starts around Sep., so the weather will be cool at that time.
The sweaters are not necessary and it is suggested to take your long-sleeved T-shirts and jeans.

in late September it will still be warm and humid in that city. maximum daytime temperatures will probably be around 30 degrees, with mild evening and nights, around 25 degrees. and be prepared for the occasional rainshower, since the rainy season is not quite over yet.