Everything You Need to Know About 'Cheap Flight Day'

August 23 can't come any sooner!

— -- We’re almost there. It's the day peak-summer prices traditionally drop from seasonal highs to off-peak lows and keep dropping (at least a bit more) until Thanksgiving. Flexible flyers, please take note.

It's called "cheap flight day" and here's what you need to know.

When: August 23. While there can be some slight differences among airlines, this is generally the day fares drop on most routes. This day, or beyond, is a cheaper time to begin a journey.

Why: According to the airline calendar, August 23 marks the start of the fall travel season because a lot of kids are back in school and demand for leisure travel drops significantly. The airlines know when we want to fly (and when we don’t) and price fares accordingly.

How much: We've seen fares drop anywhere from about 10 to 20 percent (and more, sometimes), depending on departure and destination cities.

Sales: Check out recent sales from airlines like Southwest and United and look at the travel periods covered by the deals; both give starting dates of August 23.

Cheapest days: Not all days of the week are equal. As a general rule, the cheapest days of the week to fly remain Tuesdays, Wednesdays and Saturdays while the most expensive are often on Fridays and Saturdays (domestic flights). Again, the airlines know which days are more and less popular for travelers.

Where: The August 23 price-drop is good for both U.S. domestic fares and flights to Europe. In fact we’re seeing some excellent prices on transatlantic flights now including an August 23 departure from New York to Copenhagen for $610 round-trip.

Booking: The usual rules for airfare shopping apply; book at least 30 days before you plan to take off.

What's the catch: All good things come to an end and this August deal zone does too, at Thanksgiving. On the other hand, look for an additional dip in prices during the first two weeks of November.

If you haven't had a summer vacation yet or want to squeeze in one last getaway, wait to take off until Aug. 23 and beyond and chances are very good you'll save some money.

Rick Seaney is the CEO of FareCompare, a website that curates the best deals on flights from around the world. Any opinions expressed in this column are solely those of the author.