Generally Costa Rica has two vivid seasons. Season of celebrations and dry sunny winter that attracts tourists from around the world to the spectacular sandy shorelines is called High season. Generally the seasons cover the whole country, but there are four regions where the timeframes are a bit different. So if you are in the Arenal volcano area around this time, you will find yourself in the middle of the rainy season. A similar issue is regarding the Caribbean North and South, where the rainy season is still on in December, January and April.