December

New Zealand - Grenadines

Caribbean : it's still a very good time, and tourists are not too many yet.
Djibouti, the Red Sea, Hong Kong, Jamaica South Africa : it's springtime over Cape town;
in Australia, New Zealand
South America from Montevideo to Ushuaia ; Florida, Cambodia, Haiti Bangkok is OK, wait one month before the peninsula and Phuket
India : beautiful weather over Goa
The best season ends in North Eastern Brazil

Beaches : Ivory Coast, Guadeloupe, Mexico, Oman