This is an extremely common occurrence in California. The tombstones soak up water from the sprinklers or rain and then it evaporates at night. This is due to a combination of heat sources, including necrosol, which is the soil surrounding coffins because decay = heat.
I'm only commenting because the top answer is an OPINION that couldn't be further from the truth. I hope that person educated themselves a bit in the past 14 years.
evaporation
alcohol is basicall condensation it causes fog just like hot and or cold water
Brain fog is when your mind feels like a veil of fog has been placed around you, its hard to concentrate or think. There are 5 causes for brain fog. The causes include stress, chronic fatigue syndrome and fibromyalgia, nutrient deficiencies, depression, and fatigue.
boredom
Zombies generally come from graveyards as their corpses become reanimated. And as we all know, cemeteries are always covered in a thick coating of fog at night. So it is hard to say as all zombies eventually come out from a fog-covered graveyard at some point.
i won't say it
Your breath.
fog or smog
Of course cemeteries are real but not spooky cemeteries so don't worry. In real cemeteries are not that scary so just relax.
desribe the cemeteries in Mexico
A fear of cemeteries is called Coimetrophobia.
National cemeteries began in 1921.