The mountainous geography of Costa Rica plays a very important role in the pleasant climate of the country.

In Guanacaste and especially the Peninsula of Nicoya there are two distinct seasons: the dry season, which runs from December to April, and the rainy season, which begins in May and lasts until November or early December.

Even during the rainiest months, mornings tend to be sunny and pleasant. Depending on the area, temperatures average 25°C on the coasts and beaches and between 20 and 22°C in the central plateau. Rains usually arrive in the early afternoon.

In all regions of the country, the coldest months are November, December or January; the warmest are April or May.

More than a quarter of the 51,000 square kilometers of land is strictly protected. And even beyond that, respectful treatment of the natural treasure is taught and exemplified.
There's an astounding variety of green land, amongst them tropical rainforest, cloud forests, tropical dry forests, mangroves. 
Costa Rica has an amazing wealth of 1,200 orchid and over 2,000 bromeliad species. Add more beauties like 40 of the world’s species of tropical heliconia.
But even the dry forests have their charms when the Gallinazo trees start to bloom in the summer heat, bathing the landscape in bright yellow.

Costa Rica is considered to have the highest density of biodiversity of any country in the world. While it encompasses only 0.3% of the earth's land mass, Costa Rica contains 4% of the species estimated to exist on the planet. Hundreds of these species are endemic to Costa Rica, meaning they exist nowhere else in the world. 

Although not everyone might like it, but more than 35,000 species of insects are found in the country and many more that have not been identified: warrior ants, dragonflies, beetles and many more.
The same goes for 160 species of amphibians and 225 species of reptiles with a great variety of toads, frogs, crocodiles, snakes and lizards.
Costa Rica is naturally a paradise for more than 855 species of birds. The most seen are: herons, parrots, vultures, toucans, hummingbirds.
Of course there is also a great variety of marine animals, different species of turtles (olive ridley, leatherback, green...), whales, dolphins, orcas, sharks passing through the waters of the tropics.
Last but not least you will have to share the land with lots of terrestrial animals, several species of sloths, monkeys, jaguars, deer, many rodents.