Even though Costa Rica is only 8 degrees above the equator, Costa Rica is much more “temperate” than most North American locations: Costa Rica is cooled by two oceans and no matter where you are in Costa Rica, you are always within 70 miles of a coast. A typical day starts out about 65 degrees Fahrenheit, gets up to mid-80’s, then starts dropping before sunset. Days are 12 hours year round, so there are no long, hot afternoons. Beaches are warmer (they are at sea level, of course!) and the central highlands, where 80% of the population lives, are cool enough during the day that almost none of the residents (and few hotels) have air conditioning, and warm enough at night that no one has a heating source.
Yes, we have rain! But we have a very different “style” of rain in the equatorial region to that which falls in large parts of the U.S. and Europe. Because it’s not from frozen ice crystals it is surprisingly warm. In fact, Serendipity rarely cancels events because of rain — there’s nothing quite as wonderful as riding a horse in pouring rain, riding a bike, or hiking in the jungle, or, best of all, rafting a whitewater river. About the only activity we cancel because of rain is ballooning.
There are two distinct weather zones, separated by the Continental Divide.
The Central Valley and Pacific
San Jose and the Pacific beaches are in the Pacific zone. The Pacific weather zone has very distinct rainy seasons. From late April through mid-June is a short, mild rainy season, with showers normally beginning late in the day. September through November is a REAL rainy season, with intense rains and often morning rain, but certainly rain every day.
The central mountain range (including Arenal, Poás, Irazú, and Turrialba volcanoes) creates the Continental divide, and everything “north” and “east” of the range is in the Caribbean zone. The Caribbean zone includes all the lushness normally shown in photos of Costa Rica — magnificent rainforests, cloud forests, waterfalls, misty mountains, true wild jungle. Its home to the best rafting, hiking, canyoning, horseback, and small, interesting towns and, of course, the very active volcanoes. The Caribbean (Atlantic) weather zone has rain more evenly spread year-round, but (hopefully!!) rain every day or two. Without the daily afternoon rain, the green would turn brown, the rivers would go dry, waterfalls disappear, and the mountains would become barren of the birds and butterflies and monkeys.
Unlike weather systems that travel across the United States, the weather here does not get pushed along by frontal systems (like the Jet Stream pushes big storms into the Midwest from western Canada in the winter, or hurricanes drive big rains and tornadoes all along the eastern half of the U.S. in summer). That’s the good news.
The bad news is that there are storms (we call them “temporales”) that form “right over your head”. And the storm stays right over your head sometimes 2-5 days — there’s no jet stream to push it out to sea. Big storms are magnificent, and huge, in the tropics. There’s rarely lightening — only constant, often deafeningly hard, rain. And no wind. When do we get temporales? Completely unpredictable; they can, and do, happen year round, usually 2 or 3 occur each year in each area of the country. Interestingly you can usually find some place in the country that is free of the storm. Sometimes just cross the Continental Divide and you’ll be out of a “temporal”. Or into one.
Even though Costa Rica is in the Caribbean, because Costa Rica is so far south it is extremely rare that a hurricane strikes land over Costa Rica.