The “ber” months are in! But before you start playing Christmas carols and putting together your holiday shopping list, know what to expect this month, weather-wise.

Intertropical Convergence Zone (ITCZ)

The ITCZ is an area in the atmosphere where winds from the Southern and Northern Hemispheres meet—a convergence that contributes to cloud formation. According to PAGASA, the axis of ITCZ is erratic so it may affect any part of the country, usually bringing cloudy skies and light to moderate rain showers.

Southwest monsoon

Although PAGASA Weather Forecaster Chris Perez explains that September is usually the time of the year when the southwest monsoon is nearing its termination period, this weather system can still come to play this month. The southwest monsoon, locally known as “habagat”, is composed of warm and moist air that comes from the southwest direction. It causes monsoon rains or moderate to heavy rain showers that could last for days or a week. Know more about habagat through this article.

Low Pressure Area (LPA)

The LPA is an area that has lower atmospheric pressure than its surrounding locations. This is usually formed in the Pacific Ocean where most water vapor is available. LPA brings light to moderate and sometimes heavy rain showers. This could also intensify into a tropical cyclone.

Tropical Cyclone

Tropical cyclones are the general term for bagyo, and are classified into four: Tropical Depression, Tropical Storm, Typhoon and Super Typhoon.

In September, an average of 3 to 4 tropical cyclones are expected to enter the Philippine Area of Responsibility (PAR). Based on the forecast track, most of the cyclones will affect Central and Northern Luzon.

In September 2014, three cyclones entered the Philippine boundary:

Typhoon Luis
Typhoon Luis, with the international name Kalmaegi, made landfall in Northern Luzon. Almost 8,000 individuals were affected and displaced in Regions I, II, III, IV-A, as well as the Cordillera Administrative Region (CAR) and the National Capital Region (NCR).

Tropical Storm Mario
Tropical storm Mario (internationally known as Fung-Wong) made landfall in the northern tip of Cagayan. The combined effect of Mario and the southwest monsoon caused heavy rains in Metro Manila and the rest of Luzon.
More than 2 million individuals were affected in the 27 provinces of Regions I, II, III, IV-B, V, VII, CAR and NCR. 18 dead and 16 injured were reported as Mario left the Philippine Area of responsibility (PAR).

Tropical Depression Karding
Tropical depression Karding was first spotted as a low pressure area near Iba, Zambales. Karding did not make any landfall; however, it brought moderate to heavy rain showers in the western part of Luzon.

So don’t forget to arm yourselves with umbrellas and raincoats because according to PAGASA, there will be 22 days of rain this month. Minimum temperature is pegged at 24 degrees Celsius while the maximum is at 31.6 degrees Celsius.