There are two marked seasons in Costa Rica, the dry season, from mid-November to April and the 'green season' between May and mid-November.
The busiest months in Costa Rica are during the dry season between December and April when things are busy and hotels can get booked up well in advance (especially around Christmas or Easter time).
May, June and November are amongst the best months to visit Costa Rica as the rains have either started or are about to finish and in November Costa Rica looks even greener than normal and the number of tourists is significantly lower.
The rainy season brings sunny mornings and rain in the afternoons. September and October offer the heaviest rains and dirt roads can be impassable. However the rainy season offers the best surfing conditions and white water rafting is at it's most exciting!
Costa Rica’s weather varies depending on the region. Average temperatures on The Caribbean Sea and Northern Plains are 21 Cº up to 26 Cº all year round.
The North Pacific features lower humidity levels than the Caribbean Coast and Northern Plains and average temperature is 32 Cº during the dry months.