The Climate of Costa Rica

The climate of Costa Rica is divided into two major seasons: wet and dry. The dry season typically runs from January to April and the wet season typically runs from May to November. The classifications of the seasons as wet versus dry are the amount of precipitation recorded. The average precipitation can differ depending on location. As of last year Costa Rica averaged 77.6 inches of precipitation. Different regions within the country receive more precipitation opposed to others.  Guanacaste received 94.6 inches of precipitation last year, which is relatively low, compared the highlands of Monteverde home of the “Cloud Forest” that received 144.9 inches of precipitation.

This graph above shows temperature, precipitation, and humidity in San Jose, Costa Rica. Courtesy of Google Images.

 The cloud forest of Monteverde is an incredible phenomenon where walls of mist flow through the Tilarán Mountain Range. These walls of mist are brought from the coast into the highlands from the Northeast Trade Winds. Costa Rica is situated between 8 degrees and 11 degrees north latitude. Costa Rica lies within the Intertropical Convergence Zone (ITCZ). ITCZ is where the northeast and southeast trade winds meet in a low-pressure zone. Solar heating causes the air to rise and results in an abundance of precipitation. The trade winds blow from about 11-13 miles per hour and push the clouds that are full of precipitation from the coast to the nearby highlands. The clouds are low-level clouds that drift through the canopy layer of the forest and mist.

The Monteverde Cloud Forest. The low-level cloud lay upon the forest's canopy layer and mist. Photo Courtesy of Google Images.

 El Niño Southern Oscillation (ENSO) was said to have an effect on Costa Rica a couple of years ago. ENSO refers to differences in the surface of the Pacific Ocean off of the west coast of South America and air surface pressure. The changes in temperature in the water from warm (El Niño) to cool (La Niña) are known to cause climate changes, for example, flooding or droughts.  Scientists have stated that the affects of ENSO changed Costa Rica’s climate and might be the main factor in the extinction of several rare species of frogs.  

The Golden Toad of Costa Rica was a rare frog species that is said to be extinct due to the sudden drought in the cloud forest theoretically caused by ENSO. Photo Courtesy of Google Images.

Sources:

• http://www.worldheadquarters.com/cr/climate/
• http://www.costaricaexpeditions.com/AboutCR/tempchart.php
• http://geography.about.com/od/climate/a/itcz.htm
• http://geography.about.com/od/climate/a/itcz.htm
• http://geography.about.com/od/physicalgeography/a/tradewinds.htm
• http://en.wikipedia.org/wiki/El_Niño–Southern_Oscillation
• Dr. Allen's Lectures