Arenal is fascinating all year round, it mostly depends on what you'd like to see and when you have time to go. The country's rainiest months termed the 'green season,' start in May and run until mid-November. The dry season typically lasts from mid-November until April.

Dry Season also called High Season
Pros: Perfect for those who are looking to escape the harsh winters of the Northern Hemisphere; offers endless options for travelers. Blue skies and more hours of glorious sunshine make the dry season ideal for outdoor adventures from sunrise to sunset. Though in Arenal there is a risk of rain year-round.

Cons: The tourism industry operates at full; prices are higher, attractions are more crowded, and reservations need to be made in advance.

Rainy Season also called Green Season
Pros: Trees and flowers begin to blossom, and what at some point might've been an arid countryside, finds itself turned into a paradisiacal view. Green season is ideal for nature lovers who will undoubtedly be thrilled by the variety of animal and plant species. National parks and other attractions are much less crowded and hotels are cheaper.

Cons: You'll need to plan outdoor adventures for mornings and early afternoons to avoid the rains. Some of the rugged roads become impassable without four-wheel drive during the rainy season.