Which time of the year is best for wildlife and butterflies in Costa Rica?
On the west coast, I rarely see butterflies outside. Unless they are escapees from from a nearby butterfly farm or while at a national park. I've seen them (but not in huge amounts) at the national park but no more or less than any other time of year (and I've been to the same one in December, February and April; possibly I saw less in December).
I'd think animals have their own seasons. But I'd think more when it's not rainy season. Rainy season is July(?)-November (officially the "green season ends Nov. 15).
I would say I've seen no more or less animals at specific times of the year; I've been to Costa Rica 12+ times (maybe 15?) At a variety of times throughout the year (usually November-May and one at the end of August / beginning of September).
Sorry that it's not a very specific answer. about 8 years ago