Costa Rica Climate

What is the General Pattern of Costa Rica’s Climate?

Costa Rica lies just a few degrees north of the equator, and this gives it a tropical climate totally unlike the temperate climes that most of its visitors come from. The cycle of four seasons is unknown in Costa Rica, and the temperature remains fairly constant in a warm range throughout the year. There is no true winter or autumn, due to heating of the atmosphere by a sun which remains almost constantly overhead in the same position and day length which varies only slightly over each twelve month period.

Like most tropical areas, the Costa Rica’s climate features two contrasting seasons, the dry season and the wet season. This same pattern can be found around the world in areas that lie in or close to the equatorial zone, including Africa, India, and other parts of Central and South America.

Of course, the weather is not perfectly uniform throughout these periods – there are drier times in the dry season, and wetter times in its opposite. You should plan your trip in light of what kind of weather is best for the activities you are planning.

The tropical dry season coincides with the winter and early spring of the northern hemisphere, including such places as Europe, the United States, and Canada. If you hail from the southern hemisphere, such as from Argentina or Australia, then the dry season occurs at the same time as your summer.

This season is very sunny in Costa Rica, and is the period when the dry tropical forest on the western mountain slopes is in full blossom. The days are warm, but the nights are quite cool. The dry season commences in December and lasts through the end of April, with the warmest period occurring in March and April as the time for the rains approaches.

The Costa Rican wet season begins abruptly in May, when rainfall suddenly triples as weather patterns shift. There is still plenty of sun, but rain is very frequent as well, with peak rains occurring in September and October. The rainfall in this period can turn unpaved roads into streaks of impassible, slushy mud and makes venturing outdoors a damp experience, meaning that most tourists avoid the country during these months.

The wet season lasts longer on the Caribbean side of the central Costa Rican mountains than on the Pacific side, and is marked by an earlier beginning as well. The rainfall is also heavier, while mists carried up the mountains by the northeastern trade winds sustain the cloud forests even during the dry season, and may make visiting these areas a moist experience at any time of year.

What are the Major Climate Zones of Costa Rica?

The highly varied, extremely rugged topography of Costa Rica introduces an additional complication to the climatic zones found within the country, since temperature and thus climate are also affected by altitude. The coastal lowlands are the warmest part of the country on both coasts, while temperatures fall and the climate shifts to cooler types as you ascend away from the oceanic borders. The Central Valley, which is at a considerable elevation and houses the majority of Costa Rica’s population, is a mild region, while the soaring peaks of the interior have cool climates where a dusting of snow is possible from time to time despite the lush jungle on the lower slopes.
There are four basic climate zones in Costa Rica, which can be summarized thus:

  • The Caribbean lowlands and mountain slopes are very warm, humid, and subject to very high amounts of rainfall. However, there are plenty of sunny days even in most of the rainy season, with a warm afternoon shower (or brief downpour) to break up the normally bright pattern of weather. You should not think of the Caribbean side as a dank, gloomy place, since it is actually sunny more often than it is wet and rainy, and the temperature is slightly lower than the Pacific coast’s steamy heat as well.

  • The Central Valley is mild to slightly cool, rather like the Mexican highlands where Mexico City stands but somewhat warmer on average. This leads to what is locally known as the Central Valley’s “Eternal Spring” – a very pleasant climate for those who find the tropical heat of the coasts oppressive.

  • The high mountains are cool and occasionally even cold, with misty cloud forests on the eastern sides and drier, cool weather “paramo” vegetation on the western sides – a very distinctive growth of shrubs and bushes that has an alien but beautiful and pleasant look. You should have at least a few warm clothes along if you are planning an expedition to the peaks.

  • The Pacific slopes and coastal region are a bit warmer but much drier than the Caribbean flank of the country – the northern part of this area is known as the “Gold Coast” because it is sunny, dry, and warm for much of the year, rather like the American state of California at its best.

What Temperatures Characterize the Costa Rican Climate?

The topographical variety found in Costa Rica affects temperature strongly from zone to zone of the nation, with considerably different temperatures found in at the different altitudes at the same time of year. The following table summarizes the temperatures and rainfall that you can find in each climate zone throughout the year:

Climate effect Caribbean Central Valley Mountains Pacific
Dry season rainfall 8” to 11” per month 0.2” to 1.6” per month 1.7” to 6” per month or less 5” to 11” per month
Wet season rainfall 11” to 17” per month 8” to 13” per month 13” to 16” per month or less 18” to 22” per month
Dry season high temperature 86є to 88є F (30є to 31є C) 73є to 75є F (23є to 24є C) 68є to 69є F (18є to 19є C) or cooler 90є to 92є F (33є to 34є C)
Dry season low temperature 68є to 71є F (20є to 22є C) 59є to 60є F (15є to 16є C) 53є to 57є F (12є to 14є C) or cooler 71є to 73є F (22є to 23є C)
Wet season high temperature 86є to 88є F (30є to 31є C) 76є to 78є F (24є to 26є C) 69є to 71є F (20є to 21є C) or cooler 89є to 90є F (32є to 33є C)
Wet season low temperature 68є to 71є F (20є to 22є C) 60є to 62є F (15є to 17є C) 55є to 57є F (13є to 14є C) or cooler 71є to 73є F (22є to 23є C)

For more information about the topic see Weather in Costa Rica article.