After spurts of rain in February, meteorologists forecast this month will likely remain “dry” as the temporada seca, or dry season, dictates.

But come April, residents in the Pacific region and Central Valley are in for a little surprise: an early rainy season.

The rainy season, also known as “green” season, could begin between April 21 and 25 in the north Pacific and April 26 and 30 in the central Pacific and Central Valley regions, according to Rebeca Morera, of the National Meteorological Institute (IMN). “That's at least 15 days earlier than normal,” she said.

In the southern Pacific region, which normally sees the first of the showers, rain could begin as early as March 12, she said.

An official IMN seasonal forecast is due later this month.

As for the early green season, Morera said La Niña is to blame. La Niña (The Girl) is a phenomenon characterized by unusually cold sea-surface temperatures in the eastern equatorial Pacific.

La Niña began dragging down temperatures during the last quarter of 2007, according to Costa Rican meteorologists and weather analysts worldwide.

IMN weather analysts note that temperatures this year – particularly the lows – have hovered 1 to 2 degrees Celsius below average, dipping as far down as 7 degrees Celsius (44.5 Fahrenheit) at times.