|
When
talk turns to Costa Rica's climate, hyperbole flows
as thick and as fast as the waterfalls which cascade
in ribbons of quicksilver down through the forest-clad
mountains. English 19th-century novelist Anthony Trollope
was among the first to wax lyrical: "No climate
can, I imagine, be more favorable to fertility and
to man's comfort at the same time than that of the
interior of Costa Rica." Merlin the wizard couldn't
have conjured the elements into a more blissful climate.
The
country lies wholly within the tropics yet boasts
at least one dozen climatic zones and is markedly
diverse in local microclimates, which make generalizations
on temperature and rainfall misleading.
Most
regions have a rainy season (May-Nov.) and a dry season
(Dec.-April). And the rainfall almost everywhere follows
a predictable schedule. In general, highland ridges
are wet, and windward sides always the wettest.
When
planning your trip, don't be misled by the terms "summer"
and "winter," which Ticans use to designate
their dry and wet seasons. Since the Tican "summer"--which
in broad terms lasts December through April--equates
to winter months elsewhere in the Northern Hemisphere,
and vice versa, it can be confusing.
Temperatures
Temperatures, dictated more by elevation and location
than by season, range from tropical on the coastal
plains to temperate in the interior highlands. Temperatures hover near 72deg. F on the central plateau,
average 82deg. F at sea level on the Atlantic coast
and 89deg. F on the Pacific lowlands, and fall steadily
with elevation (about one degree for every 100-meter
gain). They rarely exceed a mean of 48deg. F atop
Chirripó, where frost is frequent and enveloping
clouds drift dark and ominously among the mountain
passes. You'll definitely need a warm sweater or jacket
for the mountains, where the difference between daytime
highs and nighttime lows is greatest. Balmy San José
and the Meseta Central have an average year-round
temperature of 74deg. F.
This
being the tropics, the length of daylight varies only
slightly throughout the year. Sunrise is around 5
a.m. and sunset about 6 p.m., and the sun's path is
never far from overhead, so seasonal variations in
temperatures rarely exceed five degrees in any given
location.
Everywhere, March to May are the hottest months, with
September and October not far behind. Cool winds bearing
down from northern latitudes lower temperatures during
December, January, and February, particularly on the
northern Pacific coast, where certain days during
summer (dry season) months can be surprisingly cool.
The most extreme daily fluctuations occur during the
dry season, when clear skies at night allow maximum
heat loss through radiation. In the wet season, nights
are generally warmer, as the heat built up during
the day is trapped by clouds.
Rainfall
Rain is a fact of life in Costa Rica. The winds and
weather of two great oceans meet above Costa Rica's
jungles and mountains. Oceans--especially in tropical
latitudes--spell moisture, and mountains spell condensation.
Annual precipitation averages 100 inches nationwide.
Depending
on the region, the majority of this may fall in relatively
few days; sometimes less than 15 days a year. The
Tempisque Basin in Guanacaste, for example, receives
as little as 18 inches in drier years, mostly in a
few torrential downpours. The mountains, by contrast,
often exceed 150 inches per year, sometimes as much
as 25 feet on the more exposed easterly facing slopes!
And don't expect to stay dry in the montane rainforests
even on the sunniest days, for the humid forests produce
their own internal rain as water vapor condenses on
the cool leaves and falls.
Generally,
rains occur in the early afternoons in the highlands,
midafternoons in the Pacific lowlands, and late afternoons
(and commonly during the night) in the Atlantic lowlands.
Sometimes it falls in sudden torrents called aguaceros,
sometimes it falls hard and steady, and sometimes
it sheets down without let up for several days and
nights. Sounds like England, doesn't it!
Dry
season--"summer"--on the Meseta Central
and throughout the western regions is December through
April. In Guanacaste, the dry season usually lingers
slightly longer; the northwest coast (the driest part
of the country) often has few rainy days even during
wet season. On the Atlantic coast, the so-called dry
season occurs January-April.
Even
in the rainy season, days often start out warm and
sunny, although temporales (morning rainfall) are
not uncommon. Like many tropical destinations worldwide,
only newly arrived gringos go out without an umbrella
after noon during the wet season. Be prepared: in
the rainy season, 23 hours of a given day may be dry
and pleasant; during the 24th, the rain can come down
with the force of a waterfall. The sudden onset of
a relatively dry period, called veranillo (little
summer), sometimes occurs during July-August or August-September,
particularly along the Pacific coast.
Costa
Rica climate weather, weather in costa rica
Costa Rica is unequivocally
a tropical country, situated between 8° and 11°
North latitude, fairly close to the equator. Although
in the mountains above 2000 meters you get much cooler
temperatures, the average annual temperature for most
of the country lies between 21.7°C (71°F)
and 27°C (81°F). The coolest months are from
November through January, and the warmest from March
through May. San José, the capital, where over
a third of the population lives, stands at approximately
1170 meters altitude and has a mean annual temperature
of 20.6°C (69°F).
The
nation's climate is classically divided into two major
seasons: rainy and dry. The dry season runs from January
through May and the rainy season from May to November
and December. Locally, the seasons were named by the
early Spanish colonizers, who compared them to their
own Mediterranean climate, calling the dry months
"verano" or summer, and the rainy, grey
and gloomy months "invierno" or winter.
It is interesting to note that some of the coldest
temperatures are registered during the early dry season
or "summer". Climate is, of course, a complex
phenomenon, and there are many aspects of the weather
in Costa Rica that are worth examining in more detail,
such as the influences of wind, rain, and topography.
Weather
in the tropics is essentially a phenomenon of solar
radiation and air circulation. Intense heat at the
equator puts air in motion, and a worldwide pattern
of winds is established. The most famous of these,
for Costa Rica, are the north-easterly trade winds,
known locally as "alisios". These winds
blow with considerable force from December to March
and April. These winds, for example, are responsible
for carrying moisture in the form of mists to the
slopes of the Tilarán mountain range. These
mists are what sustain the magnificent cloud forest
ecosystem.
Rainfall
patterns, although seasonal, vary greatly in intensity
across geographical areas. Some locations receive
over 6 mts (18 ft) of precipitation per year, while
others receive under 1.5 mts (4 ft). Most of the total
rainfall for any given site (about 70%) occurs on
less than 15 days of a whole year, and will often
be experienced as days of torrential downpour. Costa
Rica may hold the world record for the amount of rainy
days at one site. Hacienda Cedral registered 359 days
of rain in 1968.
The
topography of the country also has a great influence
on the weather patterns of a given locality. As a
result the timing of the dry and rainy seasons varies
a bit on each slope of the mountain ranges that run
from the north-west to the south-east and divide the
nation into a Caribbean slope and a Pacific slope.
On
the Caribbean slope the rainy season begins from mid
to late April and continues through December and sometimes
January. The wettest months are July and November,
with a dry spell that occurs around August or September.
Major storms, called "temporales del Atlantico"
occasionally buffet this slope between September and
February, when it will rain continuously for several
days; but an average rainy season day will begin clear
with a few hours of sunshine that will give way to
clouds and rain by the afternoon. In contrast, the
driest months of February and March, might be almost
entirely without rainfall.
On
the Pacific slope the rainy season begins in May and
runs its course until November. Here again, days often
begin sunny and pleasant, with rains coming later
in the day. This is a period in which the trade winds
coming from the north-east are much reduced in intensity,
and as a result storms often come in from the Pacific
Ocean in September and October. In the northern half
of the country the Pacific slope experiences an intense
dry season, in which no rain may fall for several
months. The forests of the North-West are to a large
extent deciduous, letting their leaves fall in order
to conserve water. Winds can be very strong, occasionally
reaching speeds of 90 km/hr in the lowlands, although
they average more around 20 km/hr. The whole Central
Valley, in which the capital is situated, experiences
a mild, pleasant dry season that is matched by moderate
temperatures for most of the year, and a lower than
average amount of rainfall. Early settlers prized
the area for both its mild climate and fertile soils.
The southern half of the Pacific slope is much wetter
than its northern counterpart, with a shorter dry
season and longer and heavier afternoon rains in the
wet season.
In
a discussion of the climate in Costa Rica one cannot
omit El Niño, "The Child". It is
a poorly understood weather phenomenon that occurs
every two to seven years. It is originally detectable
as an unusual warming of a section of the Pacific
Ocean. In 1997 El Niño struck Costa Rica once
again, disrupting normal weather patterns considerably.
Some scientists have postulated that this phenomenon
might have been partially responsible for the disappearance
of several species of frogs in the late 80's, which
are extremely dependent on water. Each time it occurs
analysts across the world hold their breaths waiting
to see the effects it has on different regions, because
they can often be disastrous.
|
