These dates conventionally delimit the period of each year when most tropical cyclogenesis occurs in these parts of the Pacific.

As Adele tracked westward, it strengthened into a hurricane on June 1 and reached its peak intensity soon afterward.

The newly named Connie moved slowly to the northwest, reaching a peak intensity of 50 mph (80 km/h) on June 18.

Satellite photos taken the same day revealed cloud structure that resembled a tropical storm forming, resulting in the system being called Dolores.

The next day, Eileen turned to the northeast, reached a peak of 45 mph (72 km/h) winds, and hit western Mexico.

On July 3, data from a ship indicated winds of near 100 mph (160 km/h), which indicate a storm of Category 2 strength, near the center of Francesca.

Based on satellite imagery, Helga was believed to be gaining strength as it approached Baja California.

At one point during intensification, the storm abruptly started weakening, and on July 19, after stalling less than 118 miles (190 km) south of the tip of Baja California, Helga dissipated.

That storm, also named Ione, tracked northward, reaching a peak of 60 mph (97 km/h) winds before dissipating on July 25.

[1] A broad, flat low-pressure area persisted south of Baja California after Ione dissipated.

On July 29, a small low circulation developed with a center about 120 nautical miles (220 km) south of Manzanillo.

In a similar way to Hurricane Francesca, Tropical Storm Joyce's low level center was unclear due to a cap of cirrus clouds.

Joyce reached its peak intensity on July 31 with winds of near 60 mph (97 km/h) before weakening, becoming a depression on August 1.

Kristen was a loosely organized storm that formed from a disturbance that was causing squalls near the Mexican coast.

Without a chance to strengthen further, Lorraine weakened, finally dissipating on August 27 due to dry air.

The French refrigerated cargo carrier BIAFRA was buffeted by 38-kn southerly winds, with a barometer reading 1006 mbar, near 13'N, 132'W, by the soon to be named tropical storm Maggie at 0000 on the 21st.

Norma was an indirect but essential cause of a flood disaster in Arizona that became known as the "Labor Day Storm of 1970".

Norma's circulation fed humid unstable air into a large extratropical cyclone over Arizona.

It moved to the northwest, coming within miles of the International Date Line and Midway Island but remaining in the Central Pacific.

65 mph (105 km/h) Tropical Storm Orlene hit Mexico in eastern Oaxaca on September 8, having maintained a northeast track for its short lifetime.

[3] Storms were named Kristen, Norma, Orlene, Patricia, Rosalie, and Selma for the first time this season.

At the time, storm names within this region were assigned by the Joint Typhoon Warning Center on Guam.

the Central Pacific Hurricane Center started to issue advisories on tropical cyclones in its area of responsibility this season.