The weather in Lisbon is mild in December, and thanks to TAP Air Portugal, affordable flight options make it easier than ever for travellers to visit and fly direct. If you're lucky enough to be in Lisbon in December, make sure to sample the city's selection of Portuguese traditional Christmas cakes. Travellers can check out Tivoli Avenida Liberdade's brand-new rooftop restaurant called SEEN Lisboa, which is hosting a special New Year's Eve celebration with live music and cocktails.