Travel documents are send by email or fax. One small piece of hand luggage is allowed in the cabin. This regulation is strictly enforced. Cuba is usually very hot. However in winter, especially in January and February, it is recommended that you bring some warmer clothing, for instance a jacket, especially if you are traveling in the western part of the island.
Nights can sometimes be cold.
Casual dress is accepted in most tourist areas. However, Cubans are very proud people, and at night you are expected to dress up to go to restaurants and to dance clubs. No shorts are allowed at night in public places. Bring all personal-care items with you. Many products can be bought, but purchasing them is generally annoying and inconvenient, and your favorite brand will not be available.