Climate and seasons in Costa Rica

Costa Rica is a tropical country and does not have four seasons like in temperate zones. There are two seasons: the dry season (locally "verano") and the rainy season ("invierno" or "green season"). Temperature changes little between seasons — what changes is the amount of rain — and varies more by altitude (hotter coasts, milder Central Valley, cooler mountains) than by time of year.

Dry season (summer): approximately from December to April, with March as the driest and hottest month in most of the country. It is high tourist season: clear skies, better conditions for beaches and outdoor activities, but also more tourists, higher prices, and a need to book in advance (accommodation, national parks, tours).

Rainy season (winter or "green season"): approximately from May to November, with September and October as the rainiest months in almost the entire country. Rain usually concentrates in afternoons and nights, leaving mornings clear in many areas. It is low season: fewer tourists, better prices, and greener landscapes, a good option for those who do not mind rain and prefer to avoid crowds. July and August bring a temporary reduction in rain known as "veranillo".

Regional differences:

• North Pacific (Guanacaste): longest and most intense dry season in the country, with high temperatures between December and April.
• Central Pacific and Central Valley: more moderate seasons, with pleasant average temperatures year-round.
• South Pacific (Osa, Golfito): the rainiest area of the Pacific even in dry season; December to April are the most manageable months.
• Caribbean (Limon, Tortuguero, Puerto Viejo): without a marked dry season — it rains in a more distributed way throughout the year, with somewhat drier periods between February-March and September-October depending on the area.
• Northern Plains (La Fortuna/Arenal): rainy zone almost all year round, with evergreen forests.

Activities and times: beaches and sun activities are better in dry season (December to April), especially on the Pacific. Surfing varies by beach and type of wave depending on the time, best to check with a school or local forecast for the specific destination. For humpback whale watching in the South Pacific (Marino Ballena, Bahia Drake), the country receives two different populations at different times of year, so there is a possibility of observing them in various months — a single range applicable to the whole area was not confirmed in this verification, so for a trip focused on this activity it is advisable to confirm the exact month with a local authorized operator before booking.

High vs low season: December to April (high) has better weather for the beach but more tourists, higher prices, and a greater need to book in advance, especially during the end of the year and Semana Santa. May to November (low) offers better prices and fewer people, in exchange for a higher probability of rain in the afternoons — most destinations remain visitable, it is just advisable to plan activities in the morning.