From May to October, there's the dry season, while from November to April comes the rainy season.
The water temperatures are not equal. In the Namibe province, you should wear a 3/2 wetsuit, but near Luanda your shorts are definitely enough. The best months to surf in Angola are from July to October.
The best surf spots are located in the North of Angola. Follow interesting waves in Ambriz Beach, Barra da Kwanza, Buraco, Cabo Ledo, Chicala, Miradouro and Mussulo.
In the South, head to Quicombo and Sumbe.