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Rising temperatures, sweltering heat, and that sticky feeling – there’s no doubt that we’re already experiencing tag-init! To help you understand those weather reports better, here are some of the meteorological terms that you will often encounter this season:

Technically, we do not have “summer”. The Philippines, being a tropical country, has only two official seasons – wet and dry. Summer is experienced in temperate regions with four seasons. In our country, Dry season or tag-init is the equivalent of summer.


These are warm and humid winds coming from the Pacific Ocean, which usually affect the eastern section of the country. However, since warm air or heat is a major factor for cloud formation, Easterlies can also generate isolated thunderstorms, mostly in the afternoon or evening.

“Ridge” refers to the extended part of a High Pressure Area or an anticyclone. Unlike a Low Pressure Area, this indicates an area where the atmospheric pressure is higher than its surroundings.

Formation of clouds is usually suppressed, thus, less chance of rains. Fair weather is typically experienced when a Ridge of High Pressure Area extends over the archipelago.


Many people still get confused when they hear this. Generally fair weather means partly cloudy to cloudy skies with chances of isolated rain showers or thunderstorms. Less than half of the day will be cloudy, but rains are still possible, depending on the prevailing weather system.

On the other hand, “isolated” means localized. This means that it may be raining in your place, but not in the nearby areas. It happens when clouds are scattered in different parts of the atmosphere.


Air temperature is determined by using a weather instrument, commonly a thermometer. Also termed as “surface temperature”, it is obtained when a thermometer is exposed to the air but is sheltered from direct sun exposure.

Humidity is the amount of water vapor or moisture in the air. It can make high temperatures even more unbearable, often with a moist or “malagkit” feeling. Humidity is an important factor that affects the weather and climate as well.


Also called as “human discomfort index”, heat index refers to the temperature obtained from the high air temperature and relative humidity. It also describes how the human body perceives the heat or the warm weather.

PAGASA says full exposure to sunlight may increase the heat index by 9 degrees Celsius. PAGASA Weather Forecaster Aldczar Aurelio says the heat index is always higher than the actual air temperature. High heat indices could lead to fatigue, heat cramps, heat exhaustion or heat stroke.

Despite the fact that we are already in Tag-init Season, we may still experience rains brought by thunderstorms. Most people get confused when a downpour occurs after hours of scorching heat.

According to Former US Vice President Al Gore, also the founder of the Climate Reality Project, warmer air holds more moisture. Heat also speeds up the evaporation, bringing more clouds, which could later dump moderate to heavy rains.

During a thunderstorm, lightning and thunder also occur, along with gusty winds. Thunderstorms usually occur in the afternoon or evening, which can last for 1 to 2 hours.

El Niño is a climatic condition wherein an unusual increase in sea surface temperature (SST) or warming of the ocean is observed. In the Philippines, it mostly affects the agricultural sector due to reduced rainfall and warmer weather.

PAGASA says the prevailing El Niño may also have an effect on the current Hot and Dry season. Temperatures may continue to rise, and the duration of tag-init may be prolonged as well.

Tropical cyclone is the general term for a “bagyo,” which starts out from a cloud cluster that develops into a Low Pressure Area (LPA), which has an atmospheric pressure lower than its surrounding locations.

One common misconception during tag-init is that it’s not normal to have a Tropical Cyclone. Every month, there is a chance for a Tropical Cyclone to enter or develop within the Philippine Area of Responsibility (PAR).

In fact, we monitored “Bagyong Chedeng” just last year and it coincided with the observance of the Holy Week. Chedeng intensified as a Typhoon and even made landfall in Isabela.

This April, the average number of tropical cyclone is 0 or 1. When it comes to the track, it may make landfall or may re-curve northward away from the landmass.

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WEATHER-WISER: 10 Must-Know Weather Words | Panahon TV Blog
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Why Heavy Rains = Heavy Traffic | Panahon TV Blog