The national weather services says that the pacific coast and the Central Valley are in the period of transition between the dry and rainy season.
The agency, the Instituto Meteorológico Nacional, explained Monday that high pressure is weakening over the Caribbean and the Northern Hemisphere is warming due to the arrival of spring. That means the winds that keep away the rain are getting weak also.
The transition period, the institute noted is characterized by high variability in the weather. One day there are heavy thunderstorms and the next day is dry, it said.
This transition period begins in the last week of March and lasts through the first two weeks of April in the Central Pacific. In the Central Valley, this period continues until April 25, the institute said.
Guanacaste, which is the area that enters the dry season first and enters the rainy season last, will not see the transition period until the last half of April, said the institute.
This period also is marked by very warm days, said the institute.
The southern Pacific already is in the rainy season, it noted, and the Caribbean coast and the northern zone will see an increase in rain at the end of April and the beginning of May.
The rainy season is earlier this year. The weather institute predicts the season will arrive in the Central Valley between April 26 and April 30, a week earlier than the May 6 to 10 average.
The central Pacific will be about 10 days earlier this year ahead of the average of April 26 to 30, said the institute.
The rains are predicted for the north Pacific between May 1 and 5, nearly two weeks earlier than the May 16 to 20 average, said the institute.
The rainy season, which tourism operators like to call the green season, is marked by sunny mornings with thunderclouds building by early afternoon. The heaviest rains seem to come in October and November.