Climate and Weather of Costa Rica

Costa Rica Climate and Weather What's the weather like in Costa Rica?

Costa Rica is a tropical country located between the North latitudes of 8° and 11°. Being near the equator, Costa Rica has a temperate climate with relatively warm weather year round.

San José, the capital of Costa Rica, where over a third of the population lives, stands at approximately 1170 meters altitude and has an average annual temperature of 20.6°C (69°F).

The majority of the forests in North-West are deciduous, allowing their leaves to fall in order to conserve water. Winds can be very strong, occasionally reaching speeds of 90 km/hr in the lowlands, although the average is about 20 km/hr.

Temperatures

Costa Rica provides many different temperatures varying from tropical on the coastal plains to mild in the interior highlands depending on altitude. Temperatures on the central plateau average around 72 F, while the sea level hovers around 82 F. The Atlantic coast and Pacific lowlands range around 89 F with temperatures steadily decreasing at about 2 degrees F for every 1000 feet elevation increase. The temperatures normally don't rise above 48 F on top of Chirripó, the countries highest mountain peak. San José and the Meseta Central have an average year-round temperature of 74 F.

Costa Rica is located near the equator so daylight hours differ only slightly during the individual seasons. The sunrise is around 5 a.m. and sunset around 6 p.m. The sun's path is never far from overhead, so seasonal variations in temperatures change very little.

Throughout the country, the warmest months are March - May. Cool winds, known as alisios to the locals, travel down from northern latitudes bringing lower temperatures during December through February, particularly on the northern Pacific coast, where some days during the summer months/ dry season can get rather cool. These winds are responsible for carrying moisture in the form of mists to the slopes of the Tilarán mountain range. These mists sustain the magnificent cloud forest ecosystem.

The most extreme temperature fluctuations occur during the dry season, when clear skies at night allow more heat loss through radiation. In the wet season, nights are generally warmer, as the heat built up during the day is trapped by clouds.

Rainfall

Costa Rica, being a tropical country, always has some type of rain. The nation's climate is divided into two major seasons: rainy and dry. The dry season generally goes from January to May and the rainy season from May to December. The two distinct weather systems of the Caribbean and Atlantic oceans meet above Costa Rica's jungles and mountains. The oceans in tropical latitudes provide moisture, and the mountains provide condensation, so the annual precipitation average is high, around 100 inches nationwide.

Depending on the area, the majority of this total may fall in relatively few days; sometimes in less than 15 days a year. For example, the Tempisque Basin in Guanacaste, receives as little as 18 inches in the dry years, and the majority of it in a couple torrential downpours. The mountains, on the other hand, commonly exceed 150 inches per year, with as much as 25 feet on some of the exposed eastern facing slopes! Don't expect to stay dry in the montane rainforests even on the sunniest days, as the humid forests produce their own internal rain as water vapor condenses on the cool leaves and falls.

Generally, most days often start out warm and sunny with the occasional temporales (storms) while the majority of rain occurs in the early afternoon in the highlands, early afternoon in the Pacific lowlands, and late afternoon (and sometimes during the night) for the Atlantic lowlands. Costa Rican rainfalls can be inconsistent, with aqua ceros (sudden torrents) so always be prepared!

Dry season is summer in the Meseta Central and in the western regions is December through April. In Guanacaste, the dry season normally lasts a bit longer; the northwest coast (also the driest portion of the country) often has few rainy days even during wet season. On the Atlantic coast, the supposed dry season occurs January-April.

Even in the rainy season, although temporales (morning rainfall) are not uncommon. Be prepared: in the rainy season, 23 hours of a given day may be dry and pleasant; during the 24th, the rain can come down with the force of a waterfall. The sudden onset of a relatively dry period, called veranillo (little summer), sometimes occurs during July-August or August-September, particularly along the Pacific coast. Rainfall patterns, although seasonal, vary greatly in intensity across geographical areas. Most of the total rainfall for any given site (about 70%) occurs on less than 15 days of a whole year, and will often be experienced as days of torrential downpour. In 1968, the Hacienda Cedral area recorded a whopping 359 days of rain.

Although the country lies in the tropics, it still contains at least one dozen distinct climatic zones and is markedly diverse in local microclimates, which can make generalizations about temperature and rain misleading.

When planning your trip, don't get confused while reading about the Costa Rican summers and winters, which Ticans use to designate their dry and wet seasons. Since the Tican "summer" - which generally lasts December through April - equals the winter months elsewhere in the Northern Hemisphere, and vice versa, so it can be confusing.

A participating factor of the climate of Costa Rica is the phenomenon known as El Niño. El Niño is a misunderstood weather occurrence that happens every two to seven years. It starts as an unusual warming of sections of the Pacific Ocean. The last time El Niño hit Costa Rica was in 1997. It is suspected by scientists to have contributed to the disappearance of several species in the country but nothing has been confirmed. Hopefully soon scientists will understand the true effects of the El Niño on the ecosystems of the tropics.