Why You Need to Buy Christmas Flights (Well) Before Halloween

— -- It's annoying when Christmas decorations go up alongside the Halloween decor, isn't it? There's plenty of time to shop for Christmas, right? Yes, unless it's flights you're purchasing.

READ: Buy Thanksgiving Flights Before Labor Day, Experts Say

History suggests those who buy their Christmas flights before Halloween will get the best deals. Indeed, early October -- nearly a month before ghosts and ghouls -- is prime time for cheap Christmas flights, according to travel website Hipmunk.

That's not to say you should book today. Wait until next week.

“Travelers often think the earlier they buy airfare, the more they’ll save,” said Chris Slowe, chief data scientist at Hipmunk. “But our historical flight data consistently tells us that buying flights too early can be as bad as buying too late. The key is to know when prices will begin to steadily rise and then buy before that threshold.”

Hipmunk said those who purchase first week in October will pay an average of $398, compared with the $508 spent by those who wait until December to book. Purchasing later in October or in November yields average prices between $430 and $488.

The days you fly are just as important as when you book. CheapAir.com's Fare Index has identified the less expensive days to fly around Christmas: Dec. 18, 22, 23, 24 and 25. Most expensive dates are Dec. 19, 20 and 21.

And while you're safe to wait until next week, start looking today. Travel site Hopper's data shows Americans typically wait 12 days between shopping for flights and actually purchasing them and in that time prices rise an average of 4.5 percent.

So if you start looking today and wait 12 days to book, it's already the second week in October, and you've missed the Christmas flight sweet spot for finding the best deal.