How do you translate it is getting late in spanish?

No idea. I haven't really figured out the best of substitutes for the English 'getting'.

I would say something such as "It is very late" "It will be late soon.."

Es muy tarde : it is very late

Sera tarde pronto.. : It will be late soon..

I'm not sure on the grammatical usage of pronto, so it may not be grammatically correct, but it should get meaning across.