I don't know if AmE uses "school holidays" rather than "vacation" or "break" but the fact that you've used "school holidays" suggests that you are likely to be using BrE. If that's the case, you're more likely to hear "When are the/your school holidays?"
To clarify:
In the U.S. we have lots of holidays, including school holidays. Lucky us! But most of us don't have many vacations. Poor us!
For example, August 10 is a holiday: National S'mores Day, coming up soon! But I doubt many people use it as an excuse for a vacation.
Sometimes holidays are vacation days. Vacation days are not on always holidays, but vacations are often organized around holidays. When we say "home for the holidays," it usually means traveling to join the family during the Christmas/New Year's/Hanukha/Kwanzaa season.
A
holiday is a
holy or otherwise special day. A
vacation is a time to
vacate home, work, or both.
So, spring break is a vacation, not a holiday. S'mores Day is a holiday, not a vacation.