(ACE) index for the 2005 Pacific hurricane season as calculated by Colorado State University using data from the National Hurricane Center was 96.6 units. Broadly speaking, ACE is a measure of the power of a tropical or subtropical storm multiplied by the length of time it existed. It is only calculated for full advisories on specific tropical and subtropical systems reaching or exceeding wind speeds of 39 mph (63 km/h). The season's first tropical cyclone, Adrian, developed on May 17 and reached its peak as a Category 1 hurricane. Named storms are infrequent in May, with one tropical storm every two years and a hurricane once every four years. At the time, Adrian was the fourth earliest tropical cyclone to form in the eastern Pacific since reliable record-keeping began in 1971. Activity throughout the remainder of the season was far less notable, with 16 tropical cyclones, 15 named storms, 7 hurricanes, and 2 major hurricanes. The long-term 1971–2004 average suggests an average season to feature 15 named storms, 9 hurricanes, and 4 major hurricanes. October in particular was notably quiet, with the formation of only one tropical depression; only three other seasons, 1989, 1995, and 1996, ended the month without the designation of a named storm. Analysis of the environment suggested that most storms formed during the passage of the positive Madden–Julian oscillation and its associated upper-air divergence, which is favorable for tropical cyclone formation. Extended reprieves in tropical activity were connected to upper-level convergence. Another factor that led to a below-average season was the presence of cooler than average ocean temperatures during the peak months, helping to extend the period of lesser activity that began throughout the eastern Pacific around 1995. The 2005 became a record-tying most active in the month of September between 1966, 1992, 1994, 1997, later in 2019 forming six named storms in the basin Systems Hurricane Adrian In early to mid-May, several areas of disturbed weather moving westward from Central America aided in the formation of a broad area of low pressure well south of Mexico. A poorly-defined tropical wave became intertwined with the larger system over subsequent days, leading to the formation of a tropical depression at 18:00 UTC on May 17. The nascent cyclone intensified into Tropical Storm Adrian six hours later. Despite the effects of moderate wind shear, the system steadily organized as convection became concentrated around the center, and Adrian attained