Hordes of tourists visit the Italian seaside with dreams of dipping into cobalt-blue waters and sunbathing for hours under glorious skies. Only one thing can spoil those idyllic holiday plans: rain.

But beginning this month, the Italian island of Elba, off the coast of Tuscany, started offering tourists an unexpected guarantee: Hotels will refund guests if it rains.

Elba, the largest island in the Tuscan Archipelago, is perhaps best known as the place where Napoleon spent almost 10 months in exile more than two centuries ago. The island started the good-weather initiative, called "Elba No Rain," this year: Guests receive