These dates conventionally delimit the period of each year when most tropical cyclones form in the northeast Pacific Ocean.

The only notable storms are Hurricane Olivia, which killed 30 people, caused $30 million (1975 USD) in damage, and left thousands homeless when it made landfall in October; and an unnamed hurricane that developed at very high latitude, but had no effect on land.

Hurricanes Lily and Katrina passed close to Socorro Island and Tropical Storm Eleanor made landfall in Mexico.

[4] The only system to enter or form in the central Pacific (between 140°W and the international dateline) was an unusual high-latitude hurricane (north of 30°N), which went unnamed.

[5] The only systems to make landfall this year were Tropical Storm Eleanor and Hurricane Olivia.

Besides these two systems, Hurricane Agatha caused the sinking of a ship carrying millions of dollars worth of cargo.

[4] An area of disturbed weather about 290 mi (467 km) southwest of Acapulco formed on June 1.

After heading southwestward, it turned to the northwest and strengthened into Tropical Storm Agatha on June 2.

It reached hurricane intensity on June 3 while located about 170 mi (270 km) southwest of Zihuatanejo.

[6] The exact cause of the initial flooding was unknown, but was speculated to be primarily due to cargo shifting and not the weather.

Denise brought winds of near-gale force to parts of Mexico, but otherwise caused no damage or casualties.

[4] An area of disturbed weather developed into a tropical depression on July 10, 100 mi (160 km) south of Acapulco.

Eleanor brought 20 mph (32 km/h) winds the Manzanillo, but damage from the storm is minor due to the lack of heavy rains.

[4] An area of disturbed weather about 800 mi (1,287 km) south-southwest of Cabo San Lucas organized a tropical depression on August 11.

After heading generally westward and peaking as a weak to moderate tropical storm on August 12, Georgette slowly weakened.

The system gradually accelerated to the northwest[4] and reached its peak strength on August 15 with winds of 60 mph (95 km/h).

[4] Neither the Central Pacific Hurricane Center[10] nor the official HURDAT "best track" database of tropical cyclone location and intensity data explicitly considers them the same.

Hence, as far as official records matter, Ilsa and the unnamed hurricane of August 31 – September 5 are different tropical cyclones.

[4] The remnants of Hurricane Ilsa interacted with a mid-level trough to produce a new low-level circulation on August 31, about 930 miles (1,500 km) northeast of Hawaii.

The storm quickly developed a central dense overcast, and by 00:00 UTC on September 3 Dvorak classifications began on the cyclone.

Around that time, the storm developed an eye in the center of the convection, suggesting that it intensified into a hurricane late on September 3, located about 1,170 miles (1,885 km) south of Alaska.

[4][12][13] After maintaining hurricane status for about 18 hours, the storm weakened due to strong wind shear from the approaching cold front.

On the same day, the circulation was rapidly absorbed by the frontal system,[13] and the remnants quickly reached the coast of British Columbia.

[5][12] The remnants of the storm turned southeastward, and the low was last tracked definitively to a point north of Montana.

[13] Rain and wind reports from the Acapulco weather station suggested that a tropical depression was developing.

By 0000 UTC September 18, the system was a moderate tropical storm located about 160 mi (260 km) south of Manzanillo Lily was upgraded to hurricane status on the same day and eventually reached its peak strength.

[4] In late September, three tropical disturbances moved westward across the eastern Pacific Ocean.

Early on October 25, Olivia moved ashore just south of Mazatlán causing major damage.

It then turned to the northwest on a heading nearly directly at Clarion Island, but it dissipated on November 7[2] about 115 mi (185 km) short of landfall.

[18] The season's unnamed hurricane was the only tropical cyclone reported in the North Pacific between 140°W and the International Date Line in 1975.