“The Best Time to Book Airline Tickets is 3:15am on Fridays. Here’s Why.”

A couple of days ago I shared Peter Greenberg’s advice for the best time to book an airline ticket.

His claim was so non-sensical that I did not even bother to refute it. I left it to readers.

He said you needed to buy tickets on Wednesday at 1 am, because “most low airfares seem to appear between Sunday night and Monday night. And then, when people find those fares, they have 24 hours in which to purchase them. At midnight Tuesday, all the discount fares that weren’t purchased come flooding back into the airline’s computer systems.” But — you could only purchase these fares over the phone.

Readers submitted their own (im)plausible stories about why the best time to book tickets is actually 3:15am on Friday.

I promised to pick a ‘winning story’ and I offered a prize. So I’m reaching out to Larry V to send him a $100 gift card for his advice,

3:15am on a Friday is the best time to book a ticket (note: This is 3:15am UTC, or Universal Coordinated Time). Why? Because this corresponds to 5:15pm at the International Dateline (UTC+14).

Back when the airlines were designing more sophisticated revenue management computer algorithms in the 80s, they knew that businesses were most likely to pay higher fares, so they designed a “5 day business day window” which corresponded to the typical 9-5 business week. They designed them to load the highest fares at 9am on Monday and ended them at 5pm on a Friday. However, the programmers had to pick a starting point, and so they picked the starting point as the time at the International Date Line, so that the very first cities to experience the new business day would start buying the new fares.

At 5pm on Friday at the International Date Line, these 5-day window of higher fares expires, and the leisure fares are reloaded. It takes time to propagate through the system, so 5:15pm (or 3:15am UTC) is a good guideline to make sure all the business fares have expired.

I like it!

But for avoidance of doubt this is not true and you should not rely on it for planning travel at all. Although it is just as plausible as Peter Greenberg’s advice.

About Gary Leff

Gary Leff is one of the foremost experts in the field of miles, points, and frequent business travel - a topic he has covered since 2002. Co-founder of frequent flyer community InsideFlyer.com, emcee of the Freddie Awards, and named one of the "World's Top Travel Experts" by Conde' Nast Traveler (2010-Present) Gary has been a guest on most major news media, profiled in several top print publications, and published broadly on the topic of consumer loyalty. More About Gary »

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  1. Well…I was looking at booking an STL to PHL flight for a while, and it was $182 last night and $135 this morning!

  2. I managed to book Low tickets on the Delta website last night around 8 pm EDT. I figured hell had frozen over at that point.

  3. So Gary, what is the right answer? Or is it “no answer?”

    I fly to Denver once a month or so from southern California. Mostly United. And I can state with near certainty that on United, booking the ticket over the weekend is more expensive than waiting until Monday morning. And, it’s usually the case that it is more expensive. I have cancelled tickets twice in the last 12 months Monday morning to re-book in the 24 hour window.

    Also, here’s a nagging one: I always feel like complex routings left unbooked end up priced higher very quickly. I always figured that was due to noticing someone searching and jacking up the price temporarily. But maybe it’s just superstition. It seems like 8 hours later it’s always $50 or $100 more than the morning.

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