If you are procrastinating on purchasing that international flight for your holiday travel, you may want to place it at the top of your to-do-list.


New data has revealed that the week of Oct. 15 is one of the best times to purchase a flight for holiday travel before prices creep back up again. That means you need to jump on it, now!


According to data from Hopper, a travel app that analyzes fares to let users know the best time to book, flight prices from the U.S. to Europe for Dec. 21 to Jan. 2 are currently averaging $937 round-trip. That’s 9% less compared to flights from a month ago, and 16% below fares compared to this same time last year, as reported in Quartzy.


For flights going in the opposite direction, from Europe to the U.S., the average price for the same period is roughly $688 round trip, which is 12% lower than four weeks ago and nearly 20% less than this time last year, according to Quartzy.


If you don’t have plans to travel abroad and opting to a stay within the U.S., this week is also the best time to purchase a flight for a good deal.


U.S. flight prices for the Christmas holiday are currently averaging $307 round-trip, down 19% from this time last year.


Hopper analysts warn that passengers can expect for round-trip fares to Europe to climb at a steady rate after Halloween.


If you have flexible travel dates, or you are trying to avoid the usual holiday festivities, then Tuesday, Dec. 18 is the cheapest day to fly to your destination for the holiday.


As for the return flight, “returning on Christmas evening will guarantee the biggest savings, but if you don’t want to miss Christmas dinner, the next cheapest day to return is Friday, December 28. If you’re willing to fly on the holiday itself, however, you’re looking at savings of 22%,” Hopper analysts told Quartzy.