When is the best time to buy plane tickets?

If you want to save on your flight for the holidays, start planning … now.

CheapAir.com analyzed 917 million airfares for its annual airfare study and found that the sweet spot for travelers to snag the best deals on domestic flights is between 21 and 95 days — that’s three weeks to three months — before their departure date.

It turns out that this year has been a bit of a leveling field for airline ticket prices — only about $100 separates the priciest month (that was March — likely due to a post-pandemic surge in spring break travel) from the cheapest one (September).

And sure, you could test your luck at finding a last-minute low fare. But CheapAir found travelers who book eight to 13 days before a trip pay an average of $74 more than those who book within the prime booking window. Get your ticket less than a week out and you risk paying an average of $160 more than travelers who booked three weeks to four months ahead of time.

Buying a plane ticket too far in advance can also result in a financial penalty. Those who bought tickets 96 to 201 days in advance paid $37 more and those who purchased airfare 202 to 315 days in advance paid $90 more.

CheapAir found the best time to book varies greatly by season. You’ll want to book 89 days in advance to get the best prices for a trip in the fall, but the best time to buy for holiday travel or a winter ski trip is 68 days in advance.

If you’re wondering when’s the best day of the week to buy your airline tickets, CheapAir’s study says it doesn’t really matter. What matters is what day of the week you plan to leave or return. Travelers save an average of $82 by flying on a Tuesday or Wednesday (the cheapest days to fly) instead of on a Sunday (the most expensive day).

Nicole Dow is a senior writer at The Penny Hoarder. Staff writer/editor Tiffany Wendeln Connors updated this post for 2021.

This was originally published on The Penny Hoarder, a personal finance website that empowers millions of readers nationwide to make smart decisions with their money through actionable and inspirational advice, and resources about how to make, save and manage money.