When you buy them a little later in the season the Christmas cactus is ready to bloom, but then as the plant enjoys life on the windowsill for the next season it will throw blooms are different times. That means you might end up with a Halloween cactus like mine or maybe a Valentine's Day cactus.
The plants are triggered to bloom when there is a certain amount of daylight. When we first get them, they have been forced to bloom for the holiday. They've been grown under lights with timers so the plant will be filled with buds at Christmas.
The only way to get one to bloom at the right time is to give it the right amount of light and dark. They need about 12-14 hours of light and enjoy cool temperatures. I wouldn't worry about it though, just let them bloom when they are happy to, they will flower for a long time and are stunning.
This plant isn't really a cactus, but doesn't need much care, keep it on the dry side and it will live for decades.
Sometimes when you're lucky they will bloom all the way until Christmas. Now that's a present any gardener would love.