[2] The system was first noted as a tropical depression on October 4, 2013, within the Gulf of Thailand, to the west of Phnom Penh in Cambodia.

On October 11, the system became equivalent to a Category 5 hurricane on the SSHWS, before it started to weaken during the next day, as it approached the Indian state of Odisha.

Phailin subsequently weakened over land (becoming a Category 1 tropical cyclone) as a result of frictional forces, before it was last noted on October 14, as it degenerated into a well-marked area of low pressure.

The cyclone prompted India's biggest evacuation in 23 years with more than 550,000 people moved up from the coastline in Odisha and Andhra Pradesh to safer places.

On October 4, the Japan Meteorological Agency started to monitor a tropical depression that had developed in the Gulf of Thailand, about 400 km (250 mi) west of Ho Chi Minh City in Vietnam.

[11][12] The United States Joint Typhoon Warning Center (JTWC) subsequently initiated advisories on the depression and designated it as Tropical Cyclone 02B, before the system slightly weakened, as it passed near Mayabunder in the Andaman Islands and moved into the Bay of Bengal.

After bands of atmospheric convection had wrapped into the systems low level circulation center and formed an eye feature.

[24][25] The system subsequently made landfall later that day near Gopalpur in Odisha, at around 22:30 IST (17:00 UTC), near peak intensity.

[30][31][32][33] The Andhra Pradesh government and the Chief Minister met representatives of the Army and Navy seeking their assistance if required.

However, Srikakulam district experienced heavy rains and gale-force winds which uprooted tall trees and electric poles, shutting down power to areas.

[48] The high winds and gushing sea that the cyclone brought to Chilika Lake, India's largest coastal lagoon and home to a large number of endangered animal and plant species, had hit the eco-system that may take years to recover.

[52] Barring an early morning lightning strike at Simdradhao village in Giridih district in which a person was killed, according to police, there were no reports of rain-related casualty anywhere in the state.

[53] The areas of West Bengal, Chhattisgarh, Bihar and eastern parts of Uttar Pradesh are likely to experience heavy rainfall and strong winds.

A Merchant Ship MV Bingo was feared to have sunk in rough seas off the coast of West Bengal due to Cyclone Phailin.

[54] The eastern region of Nepal experienced heavy rainfall and winds while it was lighter in the central and western part of the country.