It's the best time to book holiday travel

  • The optimal window for booking affordable holiday flights is from now until late October.
  • After that point, prices will climb every day as December approaches.

If you're considering a winter getaway, it's time to finally set those plans in stone.

This week is the best time to book holiday flights, according to airfare prediction app Hopper.

Fares are currently averaging $307 round trip, down 19 percent from a year earlier. But after Halloween, prices climb, Hopper said.

Beginning in mid-November, the cost will go up about $3 a day and then spike in the final two weeks before Christmas, according to the app.

If your plans are flexible, you can save a lot of dough by setting fare alerts, avoiding peak days and even considering alternatives to flying, according to Jacqui Gifford, the travel director at Travel + Leisure.

Here are her tips for holiday travelers:

Know when to book: This season, a good rule of thumb is to book before Halloween because flight prices will likely fluctuate hundreds of times ahead of the holiday and get increasingly expensive 15 to 25 days prior to departure.

Best days to travel: The cheapest day to travel is Tuesday, Dec. 18 and returning on Christmas Eve. However, if you don't want to interrupt the actual Christmas holiday, the next least expensive day to return is Friday, Dec. 28. If you're willing to fly on the holiday itself, you'll save about 22 percent, according to Hopper's data.

Set fare alerts: Flight prices can fluctuate dramatically, especially in busy markets like New York and Los Angeles. Apps such as Hopper, Hitlist and Skyscanner can monitor your desired trip and notify you as soon as seats become available on a route or airfares drop, so you can score last-minute deals.

Best times to travel for your budget: Fly at undesirable times — like 4 a.m., instead of 10 a.m. — to beat the holiday crowds and peak prices.

Alternatives for flying: Consider taking the train or driving to your destination rather than flying, but the same rule of thumb applies for alternative forms of travel: Leave extra early to avoid the rush.

Book over the phone: Sure, you can easily look up prices online, but if you're booking a hotel, call and ask to speak to the manager or front desk to snag the best available rate. If you want to score a discount, a human might be more willing to work with you if they hear your story.

"On the Money" airs on CNBC Saturdays at 5:30 a.m. ET, or check listings for air times in local markets.

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