Timeline of the 2011 Pacific typhoon season
This timeline documents all of the events of the 2011 Pacific typhoon season, the period that tropical cyclones formed in the Western Pacific Ocean in 2011. Most of the tropical cyclones formed between May and November 2011. The scope of this article is limited to the Pacific Ocean, north of the equator between 100°E and the International Date Line. Tropical storms that form in the entire Western Pacific basin are assigned a name by the Japan Meteorological Agency (JMA). Tropical depressions that form in this basin are given a number with  a "W" suffix by the United States' Joint Typhoon Warning Center (JTWC). In addition, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) assigns names to tropical cyclones (including tropical depressions) that enter or form in the Philippine area of responsibility. These names, however, are not in common use outside of the Philippines. During the season, a total of 40 systems were designated as Tropical Depressions by either the Japan Meteorological Agency (JMA), the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), the Joint Typhoon Warning Center (JTWC), or other national meteorological and hydrological services such as the China Meteorological  Administration and the Hong Kong Observatory. Because the JMA runs the Regional Specialized Meteorological Centre for the Western Pacific, it assigns names to Tropical Depressions should they intensify into a tropical storm. PAGASA also assigns local names to tropical depressions which form within their area of responsibility; however, these names are not in common use outside of PAGASA's area of responsibility. For the PAGASA, 19 systems formed or entered in area of responsibility during 2011, which 10 of them directly made landfall over the Philippines. No tropical cyclones formed during January to March. The season started on April 1  with the formation of Tropical Depression 01W. February. There were no tropical updates during the whole February. March. There were no tropical updates during March 1 – March 29. Tropical Storm Haima makes landfall in Zhanjiang, Guandong, China. November. There were no tropical updates during November 10–31.