December—Sydney, Australia

Cost to Spend a Week for Two: $5,089

Visiting the Australian capital early in its summer will net you balmy temperatures and a flurry of holiday activities (including the iconic fireworks over Sydney Harbour on New Year’s). If you delay your trip till after the holidays, the average daily hotel rate falls to around $135, Booking.com finds—40% cheaper than the most expensive week of the year. For a swanky stay, the site recommends InterContinental Sydney and the Swissôtel Sydney. Take advantage of the weather by taking a picnic to one of the city’s many outdoor venues, such as Bradfield Park or Cockatoo Island. You can even order a pre-assembled gourmet feast through the Sydney Picnic Co (with baskets starting around $120).