When are children ready to understand how to tell time at what grade level?

Answer 1

Understand? ages 7 and 8 kids can understand "past" and " in the future" meanings. But all kids develope differently.
Read this: (Never get a young child a digital watch..)
http://www.parents.com/advice/toddlers-preschoolers/development/when-will-my-child-be-able-to-tell-time/