When is the best time to buy a summer vacation flight? Right now!

CHATTANOOGA (WDEF) – You probably think you have already waited too late to find a good deal on an airline ticket for this summer.

But a new study from CheapAir.com says you have timed it just right.

Buying early doesn’t always deliver the best deals.

If you book too early, airlines aren’t motivate to discount.

Too late, and you’re gambling that you will be able to book what you want.

The magic number seems to be 3.

3 months to 3 weeks before you want to fly.

The study found that prices for a typical flight will change 71 times from its open until take off.

The fluctuations move about $33 up or down every four days or so.

So their best advice is to check on possible flight six months in advance to learn the baseline, but keep checking back for a deal in the 3 window.

And when you find one, pounce.

It probably won’t last long or keep going down.

You can read more about the study at the Cheap Air Blog.