A highly dangerous heat index of 48 degrees Celsius was recorded in Calapan City, Oriental Mindoro on Saturday, prompting disaster authorities to issue urgent health warnings.

The Calapan City Disaster Risk Reduction and Management Department (CDRRMD) issued an alert at 4:00 p.m., advising residents to avoid direct sunlight and stay hydrated to prevent heat exhaustion and heat stroke.

The weather bureau PAGASA said the heat index — which combines air temperature and humidity to reflect how hot it feels — reached “danger” level, increasing the risk of heat-related illnesses, particularly for the elderly, children, and people with pre-existing health conditions.

PAGASA forecasts heat indices between 42 and 45 degrees Celsius in many parts of the country on Sunday, June 1, 2025, with some areas potentially exceeding 46°C.

The agency advised the public to limit outdoor activities, especially between 10:00 a.m. and 4:00 p.m., when heat is most intense.

A 48°C heat index poses serious health risks, including dehydration, heat cramps, and potentially fatal heat stroke. Symptoms include dizziness, nausea, and rapid heartbeat.

Health officials recommended wearing light clothing, eating cold food and fruits, and taking cool baths to manage the extreme heat.

Calapan DRRMD released emergency contact numbers for assistance: 0999-735-6447, 0915-744-9698, and 0966-029-9777, urging residents to stay alert and take necessary precautions as the heatwave continues.