Thanks to its size and the proximity of the trade winds, Saint Lucia's temperature hovers between 75 and 90 degrees year-round. Visas are not needed for visitors from North America, but a return ticket is required before entry is granted. Hewanorra International (UVF) is the main airport, but its east coast location puts it nearly an hour away from most west coast accommodations. Ferries to and from Martinique and Guadeloupe are available. The currency is the Eastern Caribbean dollar, but U.S. dollars are accepted everywhere. Hotels and restaurants add a 10% service charge, though leaving at least 5% more as a tip is expected in upmarket establishments. Electricity is 220–230 volts, but some hotels are wired for U.S. appliances.