Costa Rica’s Climate: two seasons, but how?

Costa Rica’s climate is typical of the tropics. There are two seasons: a dry season and a rainy season. The beginning and end of these seasons are determined by the intertropical convergence zone. This region of the planet, which lies in the tropics, changes position according to which hemisphere is more exposed to the sun over the course of the year. With this change in position, wind direction changes, creating the two seasons of the tropics.

Costa Rica’s climate is not as homogeneous as it may be in other parts of the tropics. It’s true that we have a dry season and a rainy season. However, the country’s rugged topography, and the presence of an ocean and a sea surrounding a narrow strip of land, mean that there are many exceptions to the rule.

We have systematized these variations in Costa Rica’s climate under two main zones of meteorological behavior: the Caribbean influence and the Pacific influence. These categories are far from being a scientific parameter, but a tool to help you better plan your trip to Costa Rica.

Costa Rica’s Climate: Pacific Influence

Geographic Region: The entire Pacific coast and the regions between the coast and the continental divide (Guanacaste plains, west face of Rincon de la Vieja, west face of Tenorio, Monteverde, south face of  , south face of Barva, south face of Irazu, Dota, Valle de El General – Coto Brus).

Dry season: from December to May.

Rainy season: from May to December.

Special features:
1- The rainy season arrives first on the Osa peninsula (mid-April) and then on the plains of Guanacaste (June).
2 – There’s a short week of cool, dry air when the climate turns to summer in the Pacific regions. Folklore has known this little dry period in the middle of the rainy season as the “Veranillo de San Juan” (“little summer of St. John” because historically it occurred around June 24, the feast of St. John).
3 – From September to the end of the period, “temporales” occur. These are days when it rains intermittently, day and night. These temporal events are responsible for maximum annual precipitation throughout the Pacific. They cannot be predicted. Travel is possible, but sun-seekers are advised to opt for another period.
4 – During the rainy season, rainfall generally occurs in the afternoon. Nights are generally dry and clear.

Costa Rica’s Climate: Caribbean Influence

Geographic Region: The entire Caribbean coast and the regions between the coast and the continental divide (Caribbean plains, Sarapiqui, northern slopes of Poas, northern slopes of Barva, northern slopes of Irazu, Turrialba valley, Boca Tapada, Arenal, Caño Negro, eastern slopes of Tenorio (Rio Celeste), western slopes of Rincon de la Vieja).

Dry season: March – April, July – late October.

Rainy season: November – March, May – July.

Special features:
1 – As a general rule, the Caribbean is more unstable than the Pacific. During the supposedly dry months of the Caribbean, it’s quite possible to have gray, rainy days.
2 – It’s important to understand that the Caribbean receives very wet winds all year round. These wet winds pour their moisture into the mountains and volcanoes. When these winds reach the Pacific, they are dry and cool, producing fine weather in the valleys and plains of the Pacific.
3 – The case of the Pacuare: the Pacuare River has its source in the Cerro de la Muerte (Pacific influence). However, the region of the river where rafting is practised is in the Caribbean. You might think that the best time for rafting is in the Caribbean summer. However, if you go rafting during the dry Caribbean months (July-October), you’re likely to encounter this much more abundant river than usual. The risk of cancelling your rafting trip is higher during the Pacific rainy season.
4- Rainfall in the Caribbean can occur at any time. However, they tend to occur mainly at night.

The middle of January. Moist winds from the Caribbean pour their humidity onto the volcanoes of the Cordillera Central.

How can I integrate all this into my travel plans?

It’s easy. Here’s a list of recommended tours based on the vacation season in the USA:

Christmas vacations: Pacific influence to be favored
Recommended itinerary: Frog tour

Winter vacations: Pacific influence to be preferred
Recommended itinerary: Family tour

Spring vacations: Caribbean and Pacific influences
Recommended itinerary: Aguila tour

Summer vacations: Caribbean influence to be preferred
Recommended itinerary: Hammock, volcano and coconut trees tour

All Saints’ Day: the Caribbean influence at its best
Recommended itinerary: Coati tour

This article is not a scientific tool, but as an agency, we are inspired by science and beauty and therefore our blogs.

Source: Natural history of Costa Rica by Daniel Janzen.