How can rain be acidic and not classify as acid rain?

Answer 1

All rain is at least slightly acidic due to the water combining with carbon dioxide in the atmopshere to form carbonic acid. Rain is considered acid rain when it is more acidic than should normally occur in nature.

Answer 2

Because the rainwater from the atmosphere is not polluted enough by the toxins from factories and nuclear weapons as well as power plants

Also, acid rain is rain that has absorbed pollutants like sulfur dioxide and has a pH lower than 5, if you wanted the chemistry of it.

Answer 3

All rain on Earth is at least slightly acidic (pH less than 7). It is considered abnormally acidic if the pH is less than 5.7. The lower the pH the greater the acidity and consequently the potential for harm increases. The presence of certain types of sulfur and nitrogen in the atmosphere mixing with rain at great enough concentrations will cause this condition.

Answer 4

Rain is normally slightly acidic because as clouds form and rain falls, the water reacts with with carbon dioxide in the atmosphere to form very weak carbonic acid that's why.