GEOGRAPHY

Santiago City covers an area of 255 square kilometers with its 37 barangays. On the south, it is bounded by the Municipality of Cordon, on the north by the Municipality of San Isidro, on the east by the Municipality of Ramon, and on the west by the Province of Quirino. The City is strategically located in Isabela, one of the country's main food granaries and second largest province.

The City lies 328 kilometers northeast of Manila and is easily accessible by land from Metro Manila and most other points in Luzon. Regular bus routes to the National Capital Region are serviced by Nelbusco, Victory Liner, Baliwag Transit, Isabela Tours, Manny Trans, Dalin Liner, Deltra, Roval and by other transportation companies.

The Magat, flowing in a west course found north of the city, is the main agricultural lifeblood of the rice producing barangays of Santiago City. Most of the irrigation water comes from the Magat River Irrigation System and irrigates 9,000 hectares of land.

The northern half of the city is traversed by the Diadi River, formerly Carig, Ilut Creek and Gunot Creek. The southern part by the Gananao River, the secondary agricultural lifeblood of rice producing areas in the south, the Dumatata River, Salat Creek, Rusu Creek, Capuntuan Creek, Dubinan River and Luchan Creek. These river courses are tapped for additional irrigation water by pumps and communal dams for gravity irrigation system.

Along the river banks of the Diadi and Gananao River are relatively flat places, broken in several areas by rising ridges and hammocks, much of which are subject to periodic flooding during the monsoon season. After every flood, fresh silt of highly organic composition are deposited making the banks of both rivers the vegetable belt in the city.

The topography of the city proper is also moderately rolling with maximum elevation variation of 12 meters based from lowest elevation of 76 meters above mean sea level at the commercial center (market) and Calao West to 84 meters above mean sea level near the City Cemetery in Calaocan.

The commercial center and market is surrounded by rolling hills; on the north, by the Provincial Road which runs on the saddle ridge of Dubinan East to Calao West; on the south by the ridge from Victory to Malvar; on the west by the ridge from Plaridel to Patul to Rosario.

CLIMATE

The climate is moderate with an average of 1.89mm rainfall over an average of 127 days of rain per year.

The heaviest amount of precipitation is during the period from the end of September to the latter part of November including December and January. During the months of February to April, the Sierra Madre mountains to the east shield the trade winds from bringing to the region rain from the Pacific Ocean.

The average wind velocity is 5 kilometers per hour for the reason that Santiago City is an inland town. Its prevailing winds during the months of September through February is from northeast, for the rest of the year, the wind is from the south. Due to the fact that the town is shielded on the east by the Sierra Madre Mountains, on the south by a secondary range of the Caraballo (Uriwong), and on the west by the Cordillera Mountain, the city is spared of the ravages of strong winds during typhoons except floods due to wide rain umbrella carried by these typhoons.

Relative humidity is 68% to 84% with the hottest temperature at 39^oC felt in June and the coldest at 24^oC felt from December to January.