This is a timeline of the 2009 North Indian Ocean cyclone season, which contains details of when a depression forms, strengthens, weakens, makes landfalls, and dissipates during the 2009 North Indian Ocean cyclone season.

It also includes information from post-storm analysis by the Joint Typhoon Warning Center (JTWC), and the India Meteorological Department (IMD) who run the Regional Specialized Meteorological Center in New Delhi, India.

RSMC New Delhi's area of responsibility is officially between 45°E and 100E which is east of the Horn of Africa and west of the Malay Peninsula.

So far this season there have been four depressions that have formed; three in the Bay of Bengal and one in the Arabian Sea.

Aila intensified further and peaked as a Severe Cyclonic Storm.