Field Notes
When to visit Osa: weather, whales and the season almost nobody considers
The question I get most is “when is the best month to visit Osa?”. The honest answer is that it depends on what you are looking for.
If you want good weather
December to April is the driest season, with February and March the driest months.
If you want whales
The best windows are August to October and January to March. Uvita, in Marino Ballena National Park, is the heart of the season.
If you want green forest and lower prices
May and June bring sunny mornings, green forest and lower prices. October and November are the rainiest months and some services close, so confirm before you travel.
More detail
Pura Osa has a guide to the best time to visit Osa, a page on whale season in Uvita and a free month-by-month sheet.