The climate in Costa Rica is hot all year round in the plains and along the coasts, while it's milder in the plateau (in the so-called tierras templadas).
Temperature variations are low, because the country is located near the Equator, so the main difference between the seasons is found in the rains. Anyway, most of the country is so rainy that it is covered with rainforests.
In the Pacific coast and the plateau there is a dry season (from December to April), and a rainy season (May to November), in which rainfall is abundant, while in the eastern plain and coast (but also in the southernmost part of the Pacific coast) the climate is equatorial, with abundant rainfall throughout the year.

Index


Caribbean coast



The east coast and the plain overlooking the Caribbean Sea are rain-soaked, and receive more than 3,000 mm (118 in) per year; here the climate can be defined as equatorial, that is, with no dry season, because the north-east trade winds that blow from November to April hit them directly. However, there are two peaks in the rains, in July and December, both with about 440 mm (17.5 in) of rain per month, and two relative minima in September-October and February-March, both with about 150/200 mm (6/8 in) per month. In this area, December is even the wettest month, and January is wetter than February and March. South of this coast, on the mountain slopes of the Braulio Carrillo National Park, precipitation reaches even 5 meters (16.5 feet!) per year!

Puerto Limón

Here is the average precipitation in Puerto Limón.
Limón - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)3052301952703253004403151452153804503565
Prec.(in)129.17.710.612.811.817.312.45.78.51517.7140.4
Days181617161819231914171721215

Along the coast of the Caribbean Sea, there is a humid heat all year round, since the winds blow constantly from the sea. Here are the average temperatures of Puerto Limón.
Limón - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)212121222323232222222221
Max (°C)292930303130303031303029
Min (°F)707070727373737272727270
Max (°F)848486868886868688868684

The sun on the east coast does not shine very often, as cloudy and rainy days are frequent all year round.
Limón - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours556654455545

Pacific coast



The Pacific coast is slightly warmer than the Caribbean coast, especially in winter, when the north-east trade winds descend from the mountains and become hot and dry: the average daytime temperatures are around the 30/32 °C (86/90 °F) in the least hot period, in October and November, while they can reach 34/35 °C (93/95 °F) in March and April, before the rainy season.
Here there is a well-defined dry season from November to April, at least in the central-northern part, while going south, the dry season becomes progressively shorter (it rains fairly often even in December and April), and in the southernmost part the climate becomes even equatorial, as happens on the coast of the Caribbean Sea.
The north-central part (province of Guanacaste, canton of Puntarenas) is particularly hot from February to April, moreover it is the least rainy area of the country, and the average rainfall drops to 1,300/1,600 mm (51/63 in) per year, in fact the savannah dominates there.

Puntarenas

Here is the average precipitation in Puntarenas, located in the north-central part of the Pacific Coast.
Puntarenas - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)64530205215175225295280130301600
Prec.(in)0.20.20.21.28.18.56.98.911.6115.11.263
Days2238192118222425156164

Here the heat is intense throughout the year, and from February to May it is torrid in inland areas, with highs around 37 °C (99 °F), while on the coast it is a bit less intense.
Puntarenas - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)222223242424232323232322
Max (°C)343434353332323232323232
Min (°F)727273757575737373737372
Max (°F)939393959190909090909090

In Puntarenas, the sun shines in the dry season, while in the rainy season the sky is often cloudy in the afternoon, when thunderstorms break out, while in the morning you can still enjoy a few hours of sunshine.
Puntarenas - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours899865565568

Quepos

Further to the south, the Pacific coast becomes more rainy, on the other hand it is less hot, especially in spring. Here are the average temperatures of Quepos, located on the coast, south of San José.
Quepos - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)222223242323232323232323
Max (°C)313232323131313030303031
Min (°F)727273757373737373737373
Max (°F)889090908888888686868688

In Quepos, 3,500 mm (140 in) of rain fall per year; as you can see, the rains are very abundant from May to November, but in December they still amount to 160 mm (6.3 in).
Quepos - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)4525401553904154454705455353501603570
Prec.(in)1.811.66.115.416.317.518.521.521.113.86.3140.6
Days745122324262626272315219

In Quepos the sun shines especially from February to April, but all in all it is seen for a few hours a day even in the wettest months, because the rains, however intense, usually occur in the afternoon or evening.
Quepos - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours788876666666

Near Quepos we find the Manuel Antonio National Park.
Further south, in the Osa peninsula and in the Golfo Dulce it rains even more: in Golfito, 4,100 mm (161 in) of rain per year fall, and there is no real dry season, even though the rainfall drops to around 100 mm (4 in) per month from January to March. In the Corcovado National Park, a tropical rainforest is found.
The climate is also equatorial in the Cocos Island, located in the Pacific Ocean, far south of the continent.

Sea temperature



The sea in Costa Rica is warm all year round, as we can see in the following table, relative to the sea temperature at Quepos, which is on the Pacific coast (but on the coast of the Caribbean Sea, the sea temperature is similar).
Quepos - Sea temperature
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Temp (°C)282829292929292928282828
Temp (°F)828284848484848482828282

Hills and mountains



In the inland areas, between the two coasts we find two mountain ranges, the Cordillera Central and the Cordillera de Talamanca.

San José

The capital city, San José, is located in the central part, on the plateau that separates the two Cordilleras, at 1,100 metres (3,600 feet) above sea level, therefore in the so-called Tierras templadas, thus it has pleasant temperatures throughout the year, with cool nights and warm days. Here are the average temperatures.
San José - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)141415171717171616161614
Max (°C)242426262726252626252524
Min (°F)575759636363636161616157
Max (°F)757579798179777979777775

In San José there is little rain from December to March, and it almost never rains in January and February. The rainy season runs from May to November, and the wettest months are September and October, with around 300 millimetres (12 inches) per month. Here is the average precipitation.
San José - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)1552045230240210240310305145401805
Prec.(in)0.60.20.81.89.19.48.39.412.2125.71.671.1
Days2025172020212222134148

The amount of sunshine is good in the dry season, while it's only mediocre in the rainy season, when the sky is often cloudy.
San José - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours788754444456

San José

At high altitudes, in the so-called tierras frìas, above 2,000 metres (6,600 feet), and even more on the slopes of the highest mountains and volcanoes, such as Cerro Chirripó, 3,820 metres (12,532 feet), or the volcano Irazú, 3,431 metres (11,257 feet), the temperatures are low, especially in the winter months. Above 3,500 metres (11,500 ft), at night it can freeze throughout the year.

Hurricanes



Costa Rica is almost always spared from the hurricanes of the Caribbean Sea, whose path is usually located to the north of the country: in fact sometimes they can affect nearby Nicaragua; therefore the area most at risk is the northern one, which may be affected by them, maybe indirectly. The hurricane season runs from June to November (though they are most likely in October and November), during the rainy season, which in any case is generally not recommended to tourists.
The first hurricane to hit directly Costa Rica was Otto in November 2016, although Hurricane Nate, which formed on the sea to the east of the country in October 2017 and then moved north, has brought even more serious damage.
Then there are the depressions and tropical storms that can be formed on the Pacific, which are usually not intense, because they affect the country in the early stages of their formation, and then move northwestward remaining on the ocean, however they can still bring heavy rains, able to cause landslides and floods.

When to go



The best time to visit Costa Rica, either for a beach holiday or for exploring its nature rich in animal and plant species, runs from January to mid-April, and in particular the months of February and March. In the lowlands it's hot, the sun shines and there is little rain, except on the east coast, which as we said is rainy throughout the year.
The capital can also be visited in December.
In the north-west (province of Guanacaste, canton of Puntarenas), since in December it rains already little, and then the spring is very hot, you may prefer December and January.
In the south-west (southern part of the province of Puntarenas, see Quepos and Golfito, Osa Peninsula), since in December it still rains enough, you can go from January to mid-April.
In the Caribbean coast you can go in February and March.

What to pack



For San José and the tierras templadas: all year round, light clothing, a sweatshirt or sweater for the evening; raincoat or umbrella from May to November.
For plains and coasts: lightweight clothes; in the rainy season, a light sweatshirt and a light raincoat for thunderstorms.
For the high mountains: warm clothes, jacket, hiking boots.

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