Costa Rica has a mainly tropical climate, with year-round warm to hot temperatures. The climate is a tropical rainforest type (Köppen climate classification Af) in the north-central to the eastern belt and the extreme southeastern tip. From the northwest to the southeast diagonally, the climate is tropical monsoon (Köppen Am). The western one-fourth of the country is a tropical savanna (Köppen Aw). A narrow strip from the central part stretching up to the eastern end has a temperate climate, with its variants (Köppen Cfb, Cfc, Cwb, Cwc). Central mountain peaks fall under the alpine zone (Köppen ET). Costa Rica is a tropical country in Central America. Panama lies in the southeast of Costa Rica, Ecuador in the south, the Pacific Ocean in the southwest, Nicaragua in the north, and the Caribbean Sea to the northeast. The tropical location and proximity to large water bodies influence the climate.
Costa Rica lies on the Caribbean Plate, 10°N of the equator. The largest island is Isla Calero, and the remotest is Cocos in the extreme southwest. The Cordillera de Talamanca and the Cordillera Central mountain ranges separate the Caribbean and Pacific drainage basins. The Cordillera de Guanacaste in the north is part of the Continental Divide of the Americas. Tropical moist broadleaf forests cover much of the Cordillera de Talamanca region. The Terraba in the southern Brunca region is the longest river with a length of 99 miles. The coastline is a vast 800 miles, including 635 miles on the North Pacific Ocean and 133 miles on the Caribbean Sea. The Irazu Volcano is the highest volcano at 3431 meters, and Lake Arenal at 33 square meters is the largest lake in the country. Mount Chirripo is the highest point at 3821 meters in Costa Rica.
Costa Rica has a tropical and subtropical climate, with two primary seasons. The dry season lasts from winter in December to summer in April. Summers are hot, dry, and cloudy. The wet season is from May to November and overlaps the winter towards the end. The conditions are humid and overcast, with frequent rainfall in many regions. Temperature variations are low, and the average annual range in Costa Rica is between 17.2°C (63°F) to 27.2°C (81°F). January sees the lowest temperatures of the year, while April records the highest. Temperatures above 37.8°C (100°F) frequently occur during the dry season. The average annual temperatures range from 27.2°C (81°F) on the coastal lowlands to 20°C (68°F) in the Cordillera Central, and below 10°C (50°F) on the highest mountain peaks. Costa Rica has several microclimates based on altitude, topography, local geography, and rainfall.
Costa Rica receives an abundant average annual rainfall of 1981.2mm (78"). September and October are the wettest months, and the rainy season contributes up to 90% of the annual precipitation. The Caribbean slopes along the Cordillera Central receive the highest rainfall of 5003.8mm (197"), and many places receive at least 2540mm (100") annually. The eastern plains and coasts, and the southernmost part of the Pacific Coast are equatorial, with rainfall throughout the year. The average seawater temperatures remain in the warm range of 27.2°C (81°F) to 28.9°C (84°F) throughout the year. Costa Rica receives annual sunshine between 1650 hours to 2700 hours annually. The average humidity is high and ranges between 74% and 90%.
The highest recorded temperature in Costa Rica is 42.8°C (109°F), set in February 1964 in Puntarenas. The lowest recorded temperature is -8.9°C (16°F), set in Cerro Chirripo.
The best time to visit Costa Rica
The best time to visit Costa Rica is usually between January and mid-April in the dry season. The sunshine is bright on the plains and coasts, and the rainfall is relatively low. A beach holiday is particularly pleasant in February and March. The northwest is preferable between December and April. The southwest is best between January and April. The Caribbean coast has the best weather from February to March. The Pacific coast is warmer than the Caribbean and receives at least 8 hours of daily sunshine in the summer. The eastern coast remains cloudy and rainy throughout the year.
The worst time to visit Costa Rica
The worst time to visit Costa Rica is during the humid and rainy period from May to November in the wet season. The period from September to October is mainly cloudy and rainy. Heavy rainfall often occurs in many parts of the country and results in landslides and mudslides. Flooding and roadblocks can become an obstruction. The seawaters are warm at 28.9°C (84°F), but cloudy skies rob the possibility of sunbathing and constant rain that of swimming. San Jose, the capital, receives hardly 4 hours of daily sunshine in the wet season. On the east coast, Puerto Limon is cloudy and rainy, with an average of 4 hours of daily sunlight.
Costa Rica is vulnerable to thunderstorms, floods, landslides, earthquakes, and volcanoes. Excessive rainfall brings floods and landslides in many regions, similar to the one in November 2010. Costa Rica lies in the Central America Volcanic Arc and is prone to volcanic eruptions and earthquakes. Six volcanoes are active out of a total of 14 in Costa Rica. Earthquakes of magnitude above 6.1 and 6.2 struck in 2009 and 2010. The Atlantic Hurricane Season from June to November is prone to tropical storms. The hurricanes from the Caribbean Sea affect the northern region at the most. Tropical storms and depressions from the Pacific usually do not make landfall. However, intense rainfall from the storms brings floods and landslides.
Weather in January
January is usually the coldest month of the year in Costa Rica, with average temperatures in the 16.1°C (61°F) to 25.6°C (78.1°F) range. San Jose, at an altitude of 1100 meters, is mostly dry in January, with 7 hours of daily sunshine. The average temperatures are between 16.1°C (61°F) to 25.6°C (78.1°F), with cloudy skies 36% to 41% of the time. The average daily wind speeds register at 5.6km/h (3.5mph), and the conditions are generally comfortable. Alajuela registers between 18.3°C (64.9°F) to 28.3°C (82.9°F), with the lowest temperatures in the third week of the month. Liberia and Puntarenas register high temperatures between 20.6°C (69.1°F) to 33.3°C (91.9°F) and remain mostly dry. The shortest days in the month have 11.5 hours of daylight, with the earliest sunset at 5.26 p.m. on January 1. The average seawater temperatures at 27.8°C (82°F) are comfortable for swimming and the ample sunshine for sunbathing on the beautiful beaches. Expect a surge in tourist numbers, as January is a pleasant time to visit Costa Rica.
Weather in February
February is generally the driest month of the year in Costa Rica, with negligible rainfall. Temperatures during the day are generally in the warm 22.8°C (73°F) to 35.6°C (96.1°F) range. Nights are mild in the zone of 13.3°C (55.9°F) to 22.8°C (73°F). The skies are partly cloudy, but the daily sunshine lasts for 8 hours to 9 hours in most places. The relative humidity is mostly at comfortable levels between 60% and 78%. A few wet places like Quesada, however, see humidity up to 85%. Puntarenas registers warm to hot temperatures in the 22.2°C (72°F) to 33.9°C (93°F) range. February first week is usually the windiest of the year on the Pacific coast, with average daily wind speeds at 12.6km/h (7.8mph). Alajuela and Heredia are warm and dry between 15°C (59°F) to 28.9°C (84°F). The average seawater temperatures remain at a warm 27.8°C (82°F) on both the Caribbean and Pacific coasts. Wear lightweight tropical clothes on the coasts and beaches, but also carry sun protection. February has ideal conditions for a trip to Costa Rica.
Weather in March
March is dry and sunny in much of Costa Rica, with 12 hours of daylight. The skies remain cloudy for 45% to 55% of the time in most regions. The average temperatures in the hilly region of San Jose are between a warm 15°C (59°F) to 26.1°C (79°F), and the sunshine lasts for 8 hours. Liberia and Nicoya see daily highs up to 36.1°C (97°F) and lows of 21.7°C (71.1°F). Quepos on the Pacific coast has many sunny days and temperatures in the zone of 22.8°C (73°F) to 32.2°C (90°F). The humidity is higher on the coasts than the interior and often reaches 85%. Sunscreen is necessary on the beaches as the sunlight scales the peak ultraviolet index of 12. Lightweight tropical clothing is best along with sunhats and sunglasses. The Caribbean coast has comfortably warm temperatures in March, with 6 hours of daily sunshine and 195.6mm (7.7") of precipitation in Puerto Limon. Temperatures increase significantly by the end of March in Costa Rica.
Weather in April
April is the hottest month of the year in Costa Rica. The average high temperatures along the western coast are in the hot zone of 31.1°C (88°F) to 36.7°C (98.1°F), with 8 hours of daily sunshine. Rio Claro registers between 22.8°C (73°F) to 32.8°C (91°F) and is one of the few wet places, with 279.4mm (11") of rainfall in April. Puerto Limon is between 22.2°C (72°F) to 30°C (86°F), while San Jose records warm temperatures between 17.8°C (64°F) and 25.6°C (78.1°F). San Jose has comfortable weather, especially in the first half of the month, when the humidity levels remain below 75%. The skies are cloudy for at least 50% of the time, even at the peak of summer. The average daily wind speeds on the coast remain in the 8km/h (5mph) to 9.7km/h (6mph) range. The north-central region receives 76.2mm (3") to 127mm (5") of precipitation, but the rest of the country is dry except for a few places. Easter holidays and fair weather make April a tourist month in Costa Rica.
Weather in May
May begins the wet season in Costa Rica, with cloudy skies and a substantial increase in precipitation. The heat index is high due to the rise in humidity and often reaches oppressive levels. San Jose records average temperatures between a warm 17.2°C (63°F) to 27.2°C (81°F) but sees an increase in humidity up to 80%. The skies are cloudy for 90% of the time, and the precipitation records an average of 231.1mm (9.1") in the month. Alajuela registers warm to hot temperatures between 19.4°C (66.9°F) to 28.3°C (82.9°F). However, the sunshine lasts only for 5 hours during the 12.5 hours of daylight. Conditions in the rainforest are humid, wet, and oppressive. The highlands above 2000 meters have cool but wet nights. The average seawater temperatures peak at 28.9°C (84°F) yet provide relief from the sticky conditions on the land. A raincoat or umbrella is necessary during outdoor visits. May is a good time for budget travelers to visit Costa Rica, with bearable weather and plenty of discounts.
Weather in June
June is cloudy, humid, and wet in most regions of Costa Rica. In the north, temperatures in Heredia and Quesada are in the warm range of 15.6°C (60.1°F) to 25.6°C (78.1°F). However, the precipitation is high between 304.8mm (12") and 355.6mm (14"). The daily sunshine barely lasts for 4 hours in most parts of the country, and cloudy skies rule the roost. The average relative humidity ranges between 80% and 95% and makes the conditions oppressive. Sweatshirts are suitable in the sticky conditions that induce much sweat. The average sea temperatures remain at 28.9°C (84°F), but there are few takers without much sunlight and frequent rainfall. Thunderstorms are common in the afternoons. The average daily wind speeds drop below 8km/h (5mph) on the coast and 4.8km/h (3mph) in the interior. June 20 is the longest day, with 12 hours and 42 minutes of daylight in San Jose. June is also the beginning of the hurricane season, which keeps the weather unstable in Costa Rica.
Weather in July
July is hot and humid in Costa Rica, with mostly cloudy skies. Puerto Limon receives 439.4mm (17.3") of precipitation during the first peak of the wet season on the east coast. The Caribbean coast has a high average humidity of 87% and average temperatures in the range of 22.8°C (73°F) to 30°C (86°F). The Pacific Coast is a little warmer than the Caribbean, with temperatures in the zone of 22.8°C (73°F) to 32.2°C (90°F) in Puntarenas. Quepos on the southern part of the coast receives heavy rainfall of 444.5mm (17.5"). Much of Costa Rica receives hardly 4 hours to 5 hours of sunshine in July with overcast skies for 90% of the time. Mid-day heat is oppressive, with the sun's ultraviolet index at the peak of 12. Afternoons are often wet due to showers or thunderstorms. The longest days of July have 12.5 hours of daylight. The average daily wind speeds remain in the 4.8km/h (3mph) to 8km/h (5mph) range, with sea breezes in the evenings. Costa Rica sees a drop in tourist numbers in July.
Weather in August
August is a wet and humid month in Costa Rica, with a high heat index. The days are mostly cloudy, and the daily sunshine lasts for less than 5 hours. The precipitation increases significantly in the second half of the month. Alajuela and Heredia register 228.6mm (9") of rainfall, Quesada 368.3mm (14.5"), Buenos Aires 452.1mm (17.8"), Quepos 490.2mm (19.3"), Rio Claro 586.7mm (23.1"), Limon 299.7mm (11.8"), and San Jose 205.7mm (8.1"). The skies are cloudy up to 92% of the time, and the daylight decreases to 12 hours and 15 minutes in most places. San Jose has comfortable temperatures between 17.8°C (64°F) and 25.6°C (78.1°F), but the sun does not often shine in the wet season. The average daily wind speeds are in the 4km/h (2.5mph) to 8km/h (5mph) range, and the direction is generally from the east. The average seawater temperatures are at a warm 28.3°C (82.9°F) and favorable for swimming enthusiasts. Expect heavy precipitation everywhere by the end of August in Costa Rica.
Weather in September
September is the wettest month of the year in much of Costa Rica except the east coast. The average precipitation ranges from 203.2mm (8") to 431.8mm (17") in the north-central region, 228.6mm (9") to 635mm (25") in the west, and 152.4mm (6") to 431.8mm (17") in the central and eastern regions. The average relative humidity is in the range of 84% to 92% and keeps the conditions oppressive along with cloudy skies. Temperature highs range between 25°C (77°F) to 32.2°C (90°F) and nightly lows are between 15°C (59°F) to 22.8°C (73°F). The hottest period is between 12 p.m. and 4 p.m., and the coldest period is between 1 a.m. and 5 a.m. Sweatshirts and raincoats are useful in the wet season along with waterproof footwear. Avoid mountain trips due to heavy rain and significant risk of landslides and mudslides. The average seawater temperatures register at 27.8°C (82°F), but the weather rarely provides seafaring opportunities. September is generally a time to avoid a visit to Costa Rica.
Weather in October
October receives heavy rainfall in most of Costa Rica. The skies are overcast at least 90% of the time, and the daily sunshine lasts hardly for 5 hours. The average high temperatures usually register in the warm to the hot range of 26.7°C (80.1°F) to 31.7°C (89.1°F). The average high temperatures remain in the mild to warm zone of 15°C (59°F) to 22.8°C (73°F). San Jose registers average temperatures in the range of 16.1°C (61°F) to 25°C (77°F), with 304.8mm (12") of precipitation and only 4 hours of daily sunshine. Quepos and Rio Claro on the western coast receive a massive 609.6mm (24") to 711.2mm (28") of rainfall. Upala and Los Chiles register temperatures in a high range of 22.8°C (73°F) to 31.7°C (89.1°F). The daylight drops to 11 hours and 45 minutes by the end of the month. The relative humidity is high in the range of 70% to 95% and keeps the conditions muggy. October sees the highest frequency of hurricanes, tropical storms, and depressions in Costa Rica.
Weather in November
November lies in the rainy season of Costa Rica, with cloudy days that receive 4 hours to 6 hours of sunshine. The precipitation is high in most places, but the possibility of rainfall decrease from 44% to 28% during the month. The average highs remain in the range of 22.8°C (73°F) to 31.7°C (89.1°F). However, many regions register temperatures below 26.7°C (80.1°F) during the day. Cartago registers warm temperatures between 15°C (59°F) to 22.8°C (73°F) and Quesada is between 18.3°C (64.9°F) to 23.9°C (75°F). San Jose is in the temperate zone of 16.1°C (61°F) to 25°C (77°F), but the precipitation decreases to 144.8mm (5.7"), and the daily sunshine lasts for 5 hours. The earliest sunshine is at 5.26 a.m. on November 1, and the latest sunset is at 5.12 p.m. on November 30 in the capital. The wind is predominantly from the east and blows with average daily wind speeds in the 4km/h (2.5mph) to 7.2km/h (4.5mph) range. November has a risk of tropical storms, and the wet weather is not favorable for a visit to Costa Rica.
Weather in December
December is the beginning of the dry season in Costa Rica, with less than 127mm (5") of precipitation in most regions. The only exception is the east coast, which experiences the second peak of the wet season. Puerto Limon on the Caribbean Coast registers average temperatures in the warm range of 22.2°C (72°F) to 30°C (86°F) and registers 449.6mm (17.7"), its highest rainfall of the year. The Pacific Coast sees a decline in precipitation and daily sunshine of more than 6 hours. Puntarenas has comfortable weather, with average temperatures in the 22.2°C (72°F) to 32.2°C (90°F) and 8 hours of daily sunshine. Although the days are cloudy, there is a perceptible decline in humidity. San Jose has comfortable weather, with average temperatures in the 16.7°C (62.1°F) to 23.3°C (73.9°F) range, and hardly 25.4mm (1") to 50.8mm (2") of rain. December 21 is the shortest day in San Jose, with 11 hours and 33 minutes of daylight. Expect an increase in the sunshine with the progress of the month. The conditions mellow by the last week of December in Costa Rica.