Costa Rica: La Niña phenomenon to affect weather through spring 2018

Event

The National Meteorological Institute (IMN) has announced that weather in the country is being influenced by the La Niña climate phenomenon. The IMN believes that La Niña began affecting the country in September and is expected to continue to affect weather through March or April 2018.

According to meteorologists, La Niña will likely cause higher than average rainfall in the Central and Southern Pacific regions and drier conditions in the Southern Caribbean region. Current forecasts indicate that the weather patterns in North Pacific, Central Valley, and North Caribbean regions will be largely unaffected. Additionally, the phenomenon is expected to lengthen the rainy season across the country, causing it to begin one to two weeks early. Additionally, cold fronts in December and January are expected to be less severe than average.

Context

La Niña is a periodic cooling of ocean surface temperatures that occurs every three to five years in the equatorial region of central and east central zones of the Pacific Ocean. During the phenomenon, ocean temperatures are typically 3 to 5°C (5.5 to 9°F) lower than normal. La Niña is part of the El Niño Southern Oscillation (ENSO), a natural global climate cycle. ENSO has two phases: the warm phase (El Niño) and the cold phase (La Niña).

The rainy season typically lasts from late May until early November in Costa Rica.

Advice

Individuals are advised to monitor local weather forecasts.