Warzone / Movie:  The Tet Offensive (1968), as seen in Full Metal Jacket (1987)

Level Of Heat: Saigon is humid as hell anyway, even without the Vietcong launched strikes on the South's key base of operations.

Corporal Joker (Matthew Modine), posted as a Marine Combat Correspondent, finds it's hard to avoid fighting in the heat of battle.

Has it cooled down since?  Renamed Ho Chi Minh City after the war, today it's a thriving metropolis, as the city's website confirms: 

"Over hundreds of years, with the vicissitude of history, the world’s various cultures seemed to have found a common place to converge in Saigon-HCM City.

The city has been gradually turned into a non-discriminating community, a cultural kaleidoscope, for people from almost every corner of the world,regardless of race and ideology."