Costa Rica has a temperate tropical climate marked by two seasons: the dry (December- April) and the wet (May-November). The average temperature throughout the year is between 71°F and 81°F. During the rainy season, also known as the green season, mornings are generally sunny followed by late afternoon showers.

Costa Rica's rainy season lasts from May until November, and may extend into mid-December. Note that the Caribbean coast has its own weather patterns, and usually experiences its driest months in September and October.

Due to the rains, the countryside becomes very lush during the wet season months. Literally every landscape transitions from brown to a vibrant green, lending the name "green season" to this low tourism period. 

Not necessarily. The months of September and October usually see the most rain and showers can be minimal – usually limited to late afternoon thunderstorms that last one or two hours. In exchange for a bit of rain, you’ll receive of up to 10-40% off high season hotel rates.

There is an average of four or more hours of sun per day during the rainy season. Mornings are usually sunny, with afternoon storms moving in later in the day.

In reality, every month in Costa Rica offers its own rewards. In terms of weather, the best times to visit are December and January, when the countryside is still fertile and green from the rainy season, but the days are sunny. Remember that travel during the green season months of May-November equals fewer crowds, discount rates and very lush landscapes.

Due to its proximity to the equator, Costa Rica experiences early sunrises and sunsets at 5:30 a.m. and 6:00 p.m., with little change throughout the year.

All roads are susceptible to landslides and flooding during the rainy season (May-November). Always look for warning signs and ask locals about road conditions before setting out. A 4WD vehicle is not necessary unless traveling the country's more rural routes, where dirt and gravel roads are the norm. 

The northeast slopes of the Central Cordillera mountains receive almost 200 inches of yearly rainfall. The Caribbean region gets 141 inches of rain annually, with the wettest months being July, November and December. This zone encompasses the entire Caribbean coast including Puerto Viejo, Cahuita, Limon, Siquirres, Guapiles and Tortuguero. The Osa Peninsula is another wet area, which receives more than 16.4 feet of rain annually. 

Often described as having a perpetual Spring climate, the Central Valley's average temperatures range from 72°F and 75°F, with little variation throughout the year. Peak daytime temperatures reach 85°F.  Relative humidity is around 75%, dropping to 69% during the dry season. 

Generally speaking, March and April are Costa Rica's hottest months. This is the peak of the dry season, before the rains begin in May. Daytime temperatures vary depending on elevation, but may reach 92°F on the beach.

Along the coast, average daytime temperatures range from of 88°F to 92°F, with evening temperatures of 71°F.

Cerro Chirripo, Costa Rica's highest peak at 12,533 feet, averages in the mid 60's during the day, and often dips below freezing at night. The lowest temperature ever registered in the park -- and the country -- was a chilly 16°F.

Typically, the months of January and February are the windiest, with persistent northeasterly trade winds that flow through the mountains. 

Guanacaste Province, which is located in Costa Rica's north Pacific, is the country's driest region. Humidity levels range from 61-87%,  and this region receives less annual rainfall than the rest of the country. Includes Liberia, Playa del Coco, Flamingo, Tamarindo, Nosara, Papagayo, Samara, Mal Pais and Montezuma. 

Due to its location, Costa Rica is rarely affected by hurricanes on the Atlantic or Pacific coasts. Hurricanes generated in the Caribbean basin can increase rainfall in the country, but direct hits are seldom experienced.