Rosberg, who was also fastest on Friday, produced a best lap of one minute 21.083 seconds.
Sergio Pérez ended 15 with 1:23 minutes on his best lap.
Trained dogs found the hidden drugs.
The racing fans dared the weather to watch the first practice.
'Checo' Pérez is on the ninth place.
The Puerto Rican singer will offer concerts in Mexico City and Monterrey.
The 29-year-old was identified as being from Chiapas.
English27/10/2015
Strong rains over Mexico City
There are thunderstorms in several areas.
They will hold a rally in the Monument to Benito Juárez.
Twenty-seven presumed victims of sexual slavery were found in the Cuauhtémoc district.