Hi Prune,
I thought the same when I was first planning to move to Singapore. My child is 3. I couldn't see any info on spring break camps or summer camps.
I first asked around on
International Schools, seems to have breaks for summer, winter, etc.... around 35-50 days off a year, depending what you choose (most closes at 5:30pm).
Then I visited different nursery and asked to see holiday schedules and it varied by night and day. Example, I ended up choosing a no frills nursery at a HDB and their hours are 7am-7pm (though you don't need to leave your child all day, but they charge as full-time rates, only). The holiday calendar there were just 20 days a year. I figured between my vacation and my spouse's there is more than 10 days a year to cover that.
I think you just have to search around.