[15] The first system of the season, One-E formed out of a tropical wave on June 18 roughly 405 miles (652 km) south-southwest of Mazatlán and initially tracked slowly northwards.

[17] However, the following day, strong wind shear caused the depression to rapidly degenerate into a trough of low pressure before dissipating off the coast of Sinaloa.

[16] Hurricane Andres formed on June 21 out of an area of disturbed weather associated with a shower and thunder storm that crossed Central America a few days earlier.

Following further organization, the system developed into a tropical depression on July 6, located roughly 435 miles (700 kilometres) south of Cabo San Lucas, Mexico.

[25] Due to the developing storm, Mexican officials posted high seas advisories for Michoacán, Jalisco, Nayarit, Baja California Sur and Colima, and advised ships to remain at port in July 6.

[37] On July 10, the NHC designated the system as Tropical Depression Four-E about 900 mi (1,400 km) south of the southern tip of the Baja California Peninsula.

The eye feature redeveloped, signaling that Carlos reintensified into a hurricane on July 14, reaching peak winds of 105 mph (169 km/h) early the next day.

[38] On July 30, the NHC began issuing advisories on Tropical Depression Six-E near the Central Pacific Hurricane Center's area of responsibility.

[40] Tropical Storm Enrique developed out of a broad area of low pressure several hundred miles south-southwest of Baja California Sur.

Later that day, Felicia rapidly intensified to a Category 4 hurricane, with maximum winds increasing to 145 mph (233 km/h), making it the strongest storm in the Eastern Pacific since Daniel in 2006.

Tropical Storm Maka was first identified on August 8, 2009, by the Central Pacific Hurricane Center (CPHC) as an area of disturbed weather roughly 835 miles (1,344 km) south of Lihue, Hawaii.

Situated over warm waters, estimated at 28 °C (82 °F) and within an area of low wind shear, the system gradually intensified as it tracked northwestward in response to a subtropical ridge to the north.

The system developed a good series of banding features and convection, and as a result, in the afternoon later that day, it strengthened into a tropical storm, the seventh in the eastern Pacific that year.

On August 16 it crossed into the Central Pacific basin as a Category 1 hurricane, and then quickly weakened to a tropical storm thereafter due to very high wind shear.

Despite over very strong as high as 45 mph (72 km/h) of shear, Guillermo survived as a weak tropical storm for a further 3 days before weakening to a depression and degenerating to a remnant low on August 19, near the West Coast.

[47] Although Guillermo remained well away from land, large swells produced by the system resulted in 6 to 8 feet (1.8 to 2.4 m) surf along the eastern coasts of the Hawaiian Islands between August 18 and 19.

While the wave axis was located over the eastern Pacific on August 20, shower and thunderstorm activity began to increase, but associated convection remained minimal.

[49] Moving across Central America earlier in the week, and slowly developed off the west coast of Mexico, about 200 miles (320 km) south of Acapulco, until it organized into a tropical depression early in the morning of August 29.

On September 4, the storm weakened into a tropical depression and made a fourth and final landfall near Santa Rosalía, Baja California Sur.

[51] Owing to the storm's slow movement, torrential rains fell over much of Baja California Sur and Sinaloa, resulting in widespread flooding.

Significant damage to infrastructure not only left people without water and power, it hampered relief efforts as many towns were isolated from surrounding areas.

Early the next day, the depression crossed the International Date Line and warning responsibility of the system was passed on to the Japan Meteorological Agency.

[60] Kevin formed from Tropical Depression Fourteen-E on August 29 from an area of disturbed weather 1,000 miles (1,600 km) southwest of Baja California.

Early on September 7, the National Hurricane Center (NHC) designated the low as Tropical Depression Fifteen-E about 1,130 miles (1,820 km) west-southwest of the southern tip of the Baja California Peninsula.

[67] After the intrusion of dry air, the convection dissipated,[68] and late on September 11, the NHC issued their final advisory on Linda after it degenerated into a remnant low.

[74] The NHC upgraded it to a tropical depression, around 4 am PDT (1200 UTC on September 16) while it was located about 340 mi (545 km) south-southwest of Cabo San Lucas, Mexico.

[80] It began to slowly weaken after reaching a peak intensity with maximum sustained winds of 45 mph (70 km/h) and a barometric pressure of 1001 mbar (hPa; 29.56 inHg).

However, as it moved north or northeast towards the Baja California Peninsula, cooler waters and shearing winds caused it to weaken to a tropical depression on October 3.

[83] In Baja California Sur, heavy rains from the remnants of Olaf resulted in flooding of low-lying areas in several municipalities, notably near the city of La Paz.

[84] Heavy rains, amounting to 1.7 in (43 mm), fell across portions of Sonora hit hard by Hurricane Jimena a month earlier; however, no damage resulted from Olaf.