Understanding what ‘heat index’ means as PAGASA warns ‘extreme caution’

April 9, 2019 - 3:00 PM
3555
State meteorologists at PAGASA recorded the highest heat index at their station in the Ninoy Aquino International Airport in Pasay City at around 2 pm on April 2. (Philstar/File photo)
FROM AROUND THE WEB

The state weather bureau recorded a peak of 40.4 degrees Celsius heat index in Metro Manila in April and will remain above the 30-degree mark during the dry season.

State meteorologists at PAGASA recorded the highest heat index at their station in the Ninoy Aquino International Airport in Pasay City at around 2 pm on April 2.

Based on their data, heat indices broke the highest recorded levels only weeks after the official start of the dry season was declared.

The top five highest heat indices were recorded on April 8 in the following cities:

  1. Dagupan City, Pangasinan – 44.1 degrees Celsius
  2. Cuyo, Palawan – 43.7 degrees Celsius
  3. San Jose City, Occidental Mindoro – 43.5 degrees Celsius
  4. Legaspi City, Albay – 42.4 degrees Celsius
  5. Sangley Point, Cavite – 42.2 degrees Celsius

Heat index is the temperature affecting the human body amid relative humidity and air temperature and is normally higher than actual air temperature.

Similar to 2018, the state agency warned that the country is expected to experience an overall heat index rating of “extreme caution” in its five-day forecast.

The maximum temperatures in NAIA station, where the heat index in Manila is recorded, is forecast to be 36.4 degrees on Wednesday, 37.3 degrees on Thursday and 37.7 degrees on Friday.

PAGASA categorizes four levels for the heat index:

  1. “Caution” if the temperature is between 27 to 32 degrees Celsius
    • PAGASA warns that “fatigue is possible with prolonged exposure and activity. Continuing activity could result heat cramps.”
  2. “Extreme caution” if the temperature is between 32 to 41 degrees Celsius
    • People are likely to experience “heat cramps and heat exhaustion” and even heat stroke with continued activities.
  3. “Danger” if the temperature is between 41 to 54 degrees Celsius
    • With this heat index, PAGASA warns that “heat cramps and heat exhaustion are likely” and heat stroke is “probable with continued activity.”
  4. “Extreme danger” for over 54 degrees Celsius
    • PAGASA warns that people might experience heat stroke at this level.

Filipinos used their wit online to express how hot they feel in this weather.

How to survive the heat

State meteorologists advised Filipinos to drink plenty of water regularly to keep the body cool.

“Water is the safest liquid to drink during heat emergencies. Avoid drinking liquor because it dehydrates the body,” PAGASA said.

It also said to wear lightweight and light-colored clothing because light colors reflect the sun’s energy while dark colors absorb it.

“Stay indoors as much as possible, if air conditioning is not available, stay on the lowest floor out of the sunshine,” it added.

PAGASA also advised people to “eat small meals more often. Avoid eating foods of high in protein which can increase metabolic heat.”