Weather-related beliefs have been passed down through generations of Filipino families. From unplugging appliances to avoiding baths during thunderstorms, many practices dismissed as superstition may actually have some basis in science.

In the Philippines, thunderstorm beliefs vary by community. Some people place scissors, knives or other metal objects outside their homes in the belief that these can drive lightning away. Others avoid wearing red clothes during thunderstorms, fearing the color could attract lightning.

While many of these beliefs are myths, weather experts say some traditional warnings have legitimate safety principles behind them.

‘Lolas’ were right ... somehow

Have your parents or grandparents ever forbidden you from bathing during a thunderstorm because you might be struck by lightning?

It turns out there is a scientific basis for the warning.

“This actually has a scientific basis. Why? Because your plumbing, especially when you are bathing and are wet, is connected to the water supply. If lightning strikes your house and the electrical current travels directly into your plumbing system, you’re in trouble. You could still get struck by lightning,” Department of Science and Technology-Philippine Atmospheric, Geophysical and Astronomical Services Administration (DOST-PAGASA) weather specialist Lean Michael A. Malabanan said.

When lightning strikes a building or nearby area, electrical current can travel through plumbing. Metal pipes and water can conduct electricity, making contact with plumbing during a thunderstorm potentially dangerous.

Malabanan said another familiar warning from older generations also has merit: unplugging electronic devices during thunderstorms.

“Parents were actually right back then [about the risk of the TV getting damaged, or your appliances getting ruined]. There is a valid basis for that. You see, if lightning strikes the house, the electrical surge could enter the appliances and destroy them. That would be a waste,” Malabanan explained.

Some beliefs, therefore, may encourage safer behavior even if their original explanations were rooted in superstition.

Others, however, could do the opposite.

One widespread belief is that placing sharp metal objects such as knives and scissors outside can ward off rain or lightning. Malabanan said there is no scientific basis for the practice.

“It is also not true that metal objects, such as knives, scissors, and the like, repel lightning. In fact, they are actually more dangerous. What you can do is install a lightning rod to protect your electronics and your home's electrical system,” he said.

Lightning rods are designed to provide a controlled path for electrical current to reach the ground, helping protect structures.

Jewelry also does not attract lightning, Malabanan said, although wearing metal can worsen burns if a person is struck.

“The painful part about wearing jewelry during a thunderstorm is that if you get struck by lightning, the metal heats up,” he said. “So, aside from the electric shock, you will also suffer burns.”

Another common belief is that using a cellphone during a thunderstorm attracts lightning.

That, too, is a myth.

“A cellphone does not emit a signal strong enough to attract lightning,” Malabanan said.

The concern changes, however, when an electronic device is connected to a wall outlet because a lightning-induced electrical surge can travel through a building’s electrical system and damage equipment.

Regardless of the myths, experts stress that the safest response to a thunderstorm is to seek proper shelter and follow official weather advisories.

What makes lightning and thunder?

Thunderstorms occur year-round in the Philippines because of the country's tropical climate, high humidity and warm temperatures.

They can also occur during the southwest monsoon, or “habagat,” when abundant moisture helps create favorable conditions for thunderstorms.

“Lightning is a massive discharge of static electricity within a thunderstorm,” DOST-PAGASA weather specialist and storm chaser Marco Polo A. Ibañez said.

Thunderstorms require three main ingredients: moisture, atmospheric instability and a mechanism that forces air upward.

Strong vertical currents called updrafts carry water droplets and other particles higher into the atmosphere. As temperatures fall, droplets freeze into ice crystals.

“The interaction, specifically the collisions, between these solid ice crystals inside the cloud is what generates a charge difference. When that charge difference becomes excessive, a spark is produced, which is what we see as lightning. Thunder, on the other hand, is the sound created by lightning,” Ibañez explained.

Lightning and thunder are produced by the same event, but people see the flash before hearing the thunder because light travels vastly faster than sound.

How are thunderstorms forecast?

Unlike larger weather systems that can be tracked days in advance, thunderstorms can develop rapidly and affect relatively small areas.

Ibañez said a thunderstorm can develop within two to three hours, making real-time monitoring essential.

PAGASA refers to short-term forecasting of such events as “nowcasting.”

Regional services divisions monitor thunderstorms using weather radars and synoptic stations. Radars provide frequent scans that allow forecasters to track cloud development in near real time.

Forecasters also use upper-air observations gathered through weather balloons to determine whether atmospheric conditions are favorable for thunderstorms.

PAGASA issues two key products through its regional divisions: thunderstorm watches and thunderstorm advisories.

“The thunderstorm watch simply gives an indication from [DOST-]PAGASA whether a thunderstorm is highly likely or not likely to occur within the next 12 hours,” Ibañez said.

For shorter time frames, PAGASA issues advisories identifying municipalities likely to experience or already experiencing thunderstorms.

The public may access warnings through PAGASA's regional channels and its PANaHON web and mobile application, which provides localized weather information and warnings.