The weather systems that affected the country during the month of October were the intertropical convergence zone (ITCZ), tail-end of a cold front, ridge of North Pacific High pressure area and the passage of three (3) tropical cyclones in the Philippine Area of Responsibility (PAR), namely; typhoon (TY) "Quedan" (Oct. 05 -06), TY "Ramil" (Oct.16-25), and TY "Santi" (Oct. 28 - Nov. 01).
The accumulated rainfall amount attributed to TY "Pepeng" (Sep. 30-Oct. 10), which was almost stationary for about one week over northern Luzon, significantly contributed to the rainfall distribution for the month of October. Likewise, TY "Ramil" and TY "Santi" also caused the way-above rainfall condition over the northern and central Luzon. These three (3) tropical cyclones brought heavy rains, widespread flooding, storm surges, landslides and massive power outages in this region resulting in the loss of many lives and damage to properties and agriculture. Near normal rainfall conditions were observed in most areas of CALABARZON (Cavite, Laguna, Batangas, Quezon), Palawan, and some areas of Region VI. However, below normal rainfall conditions were experienced in most areas of Visayas and Mindanao, while the provinces of southern Leyte, Agusan del Norte and Surigao del Norte experienced way-below normal rainfall condition. Rainfall deficiencies for the past three (3) consecutive months were also experienced over the provinces of Bohol, Capiz, and Misamis Oriental, as initial impacts of the current El Niño condition.