The National Weather Institute is warning of increased rainfall across nearly all regions of Costa Rica this weekend due to the passage of a weather trough over the country.

According to meteorologists, a weather trough, or tropical trough,  is an elongated area of low atmospheric pressure that causes air to rise and clouds to form, often resulting in strong storms.

By Friday, the tropical trough was moving from the Caribbean Sea toward the Pacific Ocean, crossing directly over Costa Rica.

Experts noted that the storms will be further intensified by the Intertropical Convergence Zone (ITCZ), a belt of low pressure near the equator that frequently generates storm activity, which currently extends across the country from the Pacific Ocean to the Caribbean Sea.

Although the disturbance is expected to move out within 48 hours, the IMN cautioned that lingering moisture may cause additional showers through Sunday. Calmer weather is likely to return by Monday.

Rainfall forecasts by region include:

• Central Mountain Range: from 50 to 100 millimeters, with the heaviest rainfall at higher elevations.

• Pacific Coast (Guanacaste, Puntarenas): 30 to 60 millimeters.

• Central Valley (San José, Alajuela, Heredia, Cartago): 15 to 40 millimeters.

• Caribbean Coast (Limón): 10 to 30 millimeters, with thunderstorms likely.

The Ministry of Public Works and Transportation (MOPT) has issued a precautionary notice for Route 32, the main highway between San José and Limón.

Officials warn that overnight closures are possible due to heavy rainfall and landslide risks. Drivers are urged to consider alternate routes, such as Route 10 through Turrialba canton (Cartago) and on to Siquirres canton  (Heredia), before rejoining Route 32 toward Limón. Traffic updates will be shared through MOPT’s official social media channels.

In response, the CNE holds an Orange Alert, the third-highest level on the emergency scale, covering the provinces of Guanacaste, Puntarenas, Alajuela, Heredia, Cartago and San José.


The alert signals a continued risk of heavy rainfall and flooding, keeping emergency response teams on high alert for possible deteriorating conditions.


The Caribbean coast (Limón province) remains under a Yellow Alert, the second level on the emergency scale, advising local emergency units to stay prepared for potential large-scale weather impacts.


As of Friday, no Green or Red Alerts,  the lowest and highest levels, respectively, had been issued beyond those already in effect.

Authorities are advising residents to take the following precautions:

• Avoid rivers, lakes, and other bodies of water during heavy rain.

• In mountain areas, watch for landslides and falling debris.

• Households and businesses in flood-prone zones should review evacuation plans.

• Drivers should beware of flooding, slick roads, and low visibility.

• Stay indoors during thunderstorms and avoid electronic devices.

• Watch for strong winds that could bring down trees or power lines.

• Call 911 to report flooding, landslides, or fallen trees.

IMN is a government agency responsible for issuing weather forecasts, hazardous weather warnings, and related services to protect the public and inform organizations.

CNE works in partnership with communities and emergency responders to strengthen the nation’s preparedness, response, and recovery from natural hazards.

MOPT is the government agency responsible for managing the country’s roads, ports, and airports, as well as overseeing public transportation policy.

A.M. Costa Rica encourages readers to share this weather advisory with family, friends, and neighbors.