By Maria Pedone
October 24, 2013

KAYAK recently announced that it will be expanding its travel search site to eight new markets in the coming weeks. Having already launched in Australia and the Netherlands, the Priceline-owned company also plans to set up in Belgium, Ireland, Mexico, Hong Kong, New Zealand, and Singapore.

Back in the US, KAYAK continues to help us find great deals on airfare and hotels—especially useful as the holiday season sneaks up. The site released their Holiday When to Book & Travel Guide, which breaks down travel tips by each holiday—and warns against waiting to book. According to KAYAK's guide, which is based on millions of queries conducted on the site last year, the cheapest flights can be found between September and mid-October. After mid-October, airfare prices skyrocket 17% for Thanksgiving, 51% for Christmas, and 25% for New Year’s Eve. These numbers hold true for domestic flights—unfortunately, international fares saw no low period during the season.

Think smart about which days you travel on, as well. Book on or as close as possible to the holiday for savings from 15% for New Year’s Eve to over 20% for Thanksgiving and Christmas Day. Departing and returning on Thanksgiving Day saw prices up to 36% below average.

Avoid weekends if you can—those traveling during weekends around Christmas saw fares 24% above average. As for New Year’s, returning after Jan. 1st could cost you to pay up to 27% more.

For more holiday travel tips, join T+L and Mashable for an airport travel Twitter chat on Wednesday, November 13th from 2pm to 3pm EDT. Follow @TravlandLeisure for details.

Maria Pedone is on the digital team at Travel + Leisure. Follow her on Twitter at @mariapedestrian.