Philippines: High temperatures forecast to persist across much of the country through at least mid-May /update 1

Hot and humid conditions are forecast to persist across much of the Philippines through at least mid-May. As of April 29, the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) has forecast dozens of locations across the country will experience an orange Danger level heat index (the second-highest level on a four-tier scale), with heat index values of 42-49 C (108-120 F) April 30-May 1. The rest of the country is under amber Extreme Caution conditions with heat index values of 34-41 C (93-106 F), with the exception of locations in the Cordillera Administrative Region which are forecast yellow Caution heat index values of 27-29 C (81-84 F). The heat index is a combination of relative humidity and the actual air temperature, providing a measure of how hot it feels; surface air temperatures of up to around 37 C (99 F) are forecast across parts of the country over the coming days but the humidity levels are increasing the levels of discomfort being felt. The public is being advised to take precautions amid the sweltering conditions, including avoiding outdoor activities during the hottest parts of the day and staying hydrated. Power outages have been reported in parts of the country in recent days due to the strain placed on the power grid during the ongoing heatwave. The Department of Education instructed all public schools across the country to hold classes online April 29-30 due to a combination of the high heat index and a strike by transport network employees.

The extended period of oppressive heat and dry conditions may produce ideal circumstances for wildfire growth throughout the region. Heatwaves also threaten vulnerable groups - such as the elderly, children, pregnant women, and those with respiratory illnesses - due to the increased possibility of heat stroke or heat exhaustion during prolonged exposure to high temperatures. These health risks could also extend to relatively healthy individuals during significant heatwave events. In addition to significantly impacting athletes and those who work outdoors, high temperatures can cause problems for people using mass transit. The lack of air conditioning and cramped vehicles during rush hour may lead to some passengers' hospitalization.

Very high temperatures may damage road surfaces, and overheated vehicles may worsen traffic problems in urban areas where congestion is already a problem. Commercial trucking disruptions might occur, as very high temperatures put more stress on vehicles, making tire blowouts more common. Major flight disruptions are unlikely at regional airports, but general aviation disruptions are possible, and some airfreight carriers could reduce cargo loads. High temperatures could lead to an increased demand for electricity, which might trigger localized brownouts or blackouts, exacerbating hazardous conditions when air conditioning is no longer possible.