Why Kayak has always been wrong about the best time to book your holiday flights

Getting There
Getting There

Past performance does not guarantee future results. Don’t forget that this oft-repeated phrase from financial planning applies to your holiday planning, too.

In an attempt to get you the best deal on flights, Kayak, an airfare search engine owned by Priceline, publishes a report each year on the “best” time to buy holiday airfare. In 2011, it said the best time to buy a US domestic ticket for US Thanksgiving was seven weeks in advance. In 2012, it said three weeks. Last year, primetime was 12 weeks out. This year, its analysts said travelers can wait up until two weeks in advance to get the best deal.


Obviously, Kayak cannot predict the future. So to make these determinations, it relied solely on the data it collected in the previous year from billions of search results displayed on its website. This means that the buy-two-weeks-in-advance figure it gave us this year was actually the best time to buy last year. It also means that when Kayak said that the best time to buy in 2013 was 12 weeks out, they were off by 10 weeks.

On average, a flyer who followed Kayak’s advice last year would have paid 4.6% more for the fare than if they were able to buy at the time of lowest fares. For fares booked at least two weeks in advance, the highest fare was only 11% more expensive than the lowest. Including fare results from within two weeks of travel, the range expanded—to 32% above the lowest fare.

So how is this year shaping up? Does it look more like last year or 2012? After repeated requests from Quartz, Kayak declined to provide data from its search results in 2014, which could better shed light on current pricing trends. Kayak says that looking at the previous year’s data is the best way to predict when to buy, and that the 2014 data is “not actionable” because it’s incomplete and backward looking. It does not explain why data from the previous year would be any more actionable, though.

Looking at how the previous years played out, we observe only two main things that have remained consistent in Kayak’s fare data.

Booking very early will cost you money. The price of a Thanksgiving-time ticket is near its most expensive in July and August.

Booking very late will cost you money. The only thing more expensive than booking in August is booking less than a week before the holiday.

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