Subseasonal forecast

Valid from  May 12-jun 8 , 2025

(4 weeks)

General comment:

The rainy season will be established this week throughout the country, with the Guatuso and Los Chiles regions being the last to enter this week. Rain is forecast between May 12 and 18, followed by a slight decrease in precipitation in the second half of May.

Fig. 1. Weekly precipitation forecast by region for the next 4 weeks.

 

1.Forecast from  may 12-18, 2025

 

This week will continue to be very unstable in the region, with heavier-than-normal rainfall in the Central and South Pacific, much less than the previous week, and normal rainfall conditions in the North Pacific and the Northern Zone. Rainfall in the Caribbean and Central Valley will also be particularly noticeable in the highlands (weekly rainfall in the Pacific is 80-180 mm, while in the Caribbean, 60-150 mm).

 

Probability of extreme: low (around 20%)
Forecast uncertainty: low

2.Forecast from may 19-25, 2025

 

Moisture levels will continue to rise in the Caribbean, favoring seasonal rainfall, although a bit of rain in the early days. Rainfall in the Central Pacific, South Pacific, and Central Valley will also be normal (60-120 mm weekly in the Pacific, 40-90 mm in the Caribbean and North Pacific, and 40-90 mm in the Central Valley).

Probability of extreme event:  low (around 20%)
Prognosis uncertainty: medium

3. Forecast from  may 26-jun 1, 2025

This week, humidity levels will remain low, with the sun shining brightly in the center and north of the country. Clear conditions will favor warmer-than-normal temperatures. The Pacific will be drier than normal, while the rest of the country will experience normal conditions.

Probability of extreme event: low (around 30%)
Prognosis uncertainty: medium

4. Forecast from  jun 2-8, 2025

Very weak trade winds and the presence of the Intertropical Convergence Zone over the country. The Intertropical Convergence Zone is expected to favor rainy conditions throughout the Pacific and Central Valley.

Probability of extreme event: low (around 20%)
Prognosis uncertainty: high

 

Forecast of extreme events from may 12-18, 2024

 

This week, there is a moderate possibility of cyclogenesis, meaning a low-pressure system could form north of Panama, generating rainy conditions in the southern Pacific of Central America. There is a high possibility of a rainy scenario in Costa Rica and a very low possibility of direct impact from a tropical cyclone.

Fig. 2. Forecast of extreme events for the next 2 weeks (training areas).

 

 

Forecaster: Daniel Poleo
Maps: Nury Sanabria Valverde
Unidad de aplicaciones climáticas
Departamento de Desarrollo/IMN