4. Climate, Weather, and Related Matters

Costa Rica – Cactus and Cows is a watercolor painting done by the author. It was inspired by the cactus corral in the nearby town of Huacas and by the Brahma cattle the roam the ranches in Guanacaste.

Costa Rica has a tropical climate throughout the country. Temperatures are moderated by local geography rather than by season. The difference in the high temperature (degrees Fahrenheit) on any given day from near sea level to a mountain town at 4,000 feet might vary by twenty degrees, say from 90 at sea level to 70 in the mountains, while the temperature difference for the daily high at a given point on the Pacific coast will only vary by about 7 to 10 degrees across 365 days. At the beach, the temperatures will range each day from a low in the mid 70’s to a high in the high 80’s or low 90’s.  Costa Rica uses the metric system and the Centigrade thermometer. There really is no reason to care about the temperature while you’re there but if you’re curious here are some tips to help you convert. 82 degrees F. is 28 degrees C. and roughly speaking, one degree C is a little less than two degrees F. So if someone tells you that the temperature will be 32 just subtract 28 and multiply the difference by 2 and add that to 82. So 32C is about ((32 – 28) X 2) + 82 or 90F. Generally, locals talk about just 2 seasons, summer and “the green season” also called winter. Technically, the time of year that they call summer, from late November until about May 1, is really winter in pure geographic terms because the country lies north of the equator but local terminology uses southern hemisphere seasonal descriptions. There is no description of spring or autumn. In the northwest Pacific Province of Guanacaste, the heart of the burgeoning real estate and tourism markets, the period from around December 1 to late April sees virtually no rain. The “green” season entails typical tropical showers in the late afternoon and at night in May and June with a bit of a let up in July and August and then a more impactive amount of rain in September and October. Even then however, the sun shines most every day in the morning and until mid day. The mountains, the Caribbean coast, and the south see more rainfall year round. The Province of Guanacaste, the focus of the growth, goes from a desert type look, similar to the area around Sacramento, CA in the dry season to lush forest and fields within a couple of weeks when the rains start coming in late April. The local climates certainly play a role in the pace of development of the country as a tourist and retirement destination. Naturally the regions with the least amount of rain are most desirable for tourism and retirement. There are no Atlantic hurricanes and Pacific hurricanes which occasionally threaten Mexico and Hawaii are not a threat. Costa Rica is simply too far east and too far south to be seriously affected by either Pacific or Atlantic hurricanes. No hurricane has ever struck this country. Heavy rains spawned by the storms have been experienced on occasion. The important point is that you can safely plan a summer (U.S. summer) vacation without worrying about your trip being interrupted by a hurricane. Of course if your travel plans involve a change of planes in Miami, Charlotte, Atlanta, or Houston, four of the major gateways to Costa Rica, your air travel could be affected. Other than the seasonal heavy rains, mostly in September and October, the only natural disaster threats to Costa Rica are the possibilities of an earthquake or a volcanic eruption. In 2011 an earthquake that measured 6.5 on the Richter scale struck in the mountainous region just north of the capital city, San Jose. In September of 2012 a larger quake, measuring 7.6 struck along the Pacific coast of the Nicoya Penninsula in the Northwestern part of the country. There was damage to some roads and homes but just a few fatalities. The building codes in Costa Rica for earthquake related matters mirror those of Japan and California. Our condominium is probably less than 50 miles or so from the epicenter of this large 2012 earthquake but we suffered no damage. Occasionally one of the country’s five active volcanoes (Poás, Arenal, Rincón de la Vieja, Irazú, and Turrialba) experiences a major eruption but these are not near major population centers. Since volcanic eruptions are mostly predictable and therefore pose no sudden unexpected threat, visiting the volcanoes is a popular tourist activity. Surprisingly, you will not find insects to be much of a problem. Although almost all dining is out of doors you will encounter few flies and fewer mosquitoes than you would on a summer evening at home. Almost all restaurants will have a can of insect repellent handy for those of us who seem to attract the critters more readily.

Just for fun, here’s a little piece that I wrote about mosquitos in Guanacaste a few years ago.

There once was a nasty mosquito,

That buzzed in my ear, drove me out of my mind.

I thought that the spray made me incognito

Apparently not, I was easy to find.

I swung and I slapped and I tensed all my muscles

But try as I might she stole my corpuscles.

T. Spurr - 2007

There are some creatures that just don’t endear themselves to the human population of our biosphere, Earth.  Cockroaches, snakes, and mosquitoes quickly come to mind. 

Alas, they all take their place in the magical, mystical wonder that is nature.   Mosquitoes are an important food source for a wide variety of birds whose voices bring us joy, of fish that shimmer in the water, of frogs that delight us as children, and even of bats.  Now don’t get me started on why we need bats; to eat mosquitoes if nothing else.  It is all a big interdependent cycle, you know.  Bats are an important pollinator and seed distributor for trees, without which we can’t live.  No trees, no oxygen, no soil, and on and on.  As an interesting aside, researchers identified a cave in Mexico in which a colony of bats estimated at 800,000 individuals were calculated to consume 3,805 kg of mosquitoes per night.  For those among us who don’t do metric, that’s close to 8,400 pounds of mosquitoes.  Maybe it’d grab you more if we said that die fleidermaus (bats – auf Deutsch) each night ate the weight of two of your grandfather’s Buicks. 

Anyway, back to the mosquitoes.  It is a natural question for visitors from temperate climates such as most of the U.S. to ask if mosquitoes are a problem here, particularly as these visitors eye the beauty of our thousands of acres of mangrove, estuary, and tropical forest. 

So here’s a little bit of information that will shed some light on that topic.  According to Inbio, the National Institute for Biodiversity here in Costa Rica, there are fourteen varieties of mosquitoes that call Costa Rica “home.”  Of those fourteen, three, maybe four, hang out around here in Guanacaste.  Unfortunately, one of those is Aedis aegypti, the mosquito that carries and spreads Dengue fever.  None of the mosquito species that are indigenous to this part of Costa Rica are salt water breeders.  That means that a large part of the wet areas that you see here are not friendly to the mosquitoes.  Mosquitoes need water in order to lay eggs and multiply.  While some species of mosquitoes do breed in salt water, the Costa Rican residents don’t unless salinity is quite low.  Aedis aegypti can breed in water that is 30% or so salt water.  Water that is commonly a mix of fresh and salt water is referred to as “brackish” water.  Depending on how far back into the estuary one travels and depending on the amount of recent rainfall, the flow of the tide, etc, the salt content of the mangrove and the estuary vary a lot and at some times likely reach a point farther back from the tidal areas where mosquitoes might breed but the water is flowing, not stagnant and long standing pools of stagnant water, not what’s there, are what the mosquitoes need. 

The mangrove is also full of many of the creatures for whom the mosquitoes are dinner.  The natural waterways aren’t the problem.  In the absence of man, mosquitoes find water in which to breed inside old coconut shells, inside of large flowers, in hollows in trees, etc.  In the presence of man there are often many more “containers” for stagnant water, the boudoir of choice, for mosquitoes.  Tires, empty cans, buckets, etc. become breeding grounds for these unwelcome insects.  The natural breeding places dry up completely here in our dry tropical forests in Guanacaste during the “dry season,” December to April.  Since mosquitoes life spans are measured in days, there won’t be mosquitoes here during those months unless we provide them with places to procreate.  Construction sites, unfortunately are often stagnant water parks of the first order.  The Costa Rican Ministry of Health does a good job of policing construction sites for situations that can encourage the spread of Dengue but of course they don’t find them all.  

Another useful thing to know about mosquitoes is that they don’t travel very far from home.  In the absence of a hurricane or some similar means of transportation, the farthest a mosquito ever gets from his or her birthplace is about 200 meters.  In simple terms, if we are diligent about eliminating artificial sources of stagnant water, it isn’t an overwhelming task to keep these pesky, pesty critters off our backs – and hands and faces and ankles. 

What about the lovely “water features” that we see in some homes, you ask.  Well as long as water is flowing, e.g. has a pump moving through fountains and such, and/or in the presence of aquatic pets, e.g. goldfish, Koi, no problemo.  Keeping chlorine in the water as we do with swimming pools also solves the problem. 

Any other questions of a mosquitoish nature?