1977–78 South Pacific cyclone season

The 1977–78 South-West Indian Ocean cyclone season was a near-average season, with eight tropical cyclones forming.

Tropical Cyclone Tessa
Tessa precursor tropical depression was first noted on December 5, while it was located in the southern Line Islands of Kiribati. Over the next couple of days, the system moved southeastwards and gradually intensified, before it was named Tessa by the FMS during December 7.

During December 9, the system moved in between Puka Puka and Reao as it continued to weaken and move south-eastwards towards the Gambier Islands. The system was last noted during December 11, while it was located about 590 km to the northeast of Adams Town in the Pitcarn Islands. As the system moved through the Tuamotu Islands of French Polynesia, Tessa caused significant precipitation over the islands, with the Puka Puka weather station recording a 24-hour rainfall total of 154.2 mm during December 8.

Tropical Cyclone Anne
For several days during the week building up to Christmas 1977, a tropical disturbance persisted about 925 km to the northeast of Fiji and to the northwest of Samoa. A distinct cyclonic circulation subsequently started to develop during December 23, while it was located about 740 km to the northeast of Vanua Levu. Over the next day the system moved south-westwards and passed within 75 km of Futuna, before it was named Anne by the FMS during December 24, as satellite pictures showed that a tropical cyclone was developing. During December 25, the winds were indirectly estimated to be off gale-force, as it passed south-westwards through the Fijian Islands.

Tropical Cyclone Diana
During February 15, a tropical depression developed within the South Pacific Convergence Zone, to the west of French Polynesia's Society Islands. Over the next couple of days, the system moved eastwards towards Mopelia while gradually developing further, before it was named Diana by the FMS during February 16.

Tropical Cyclone Ernie
During February 17, the FMS started to monitor a tropical depression that had developed, about 560 km to the northwest of Udu Point in Fiji. During that day, the system deepened as it moved south-eastwards towards Fiji before the FMS named it Ernie.

Season effects

 * Steve || November 24 – December 4 || bgcolor=#|Category 2 tropical cyclone || bgcolor=#|60 kn || bgcolor=#|965 hPa || || || ||
 * Tessa || December 5 – 11 || bgcolor=#|Category 1 tropical cyclone || bgcolor=#|40 kn || bgcolor=#|990 hPa || || || ||
 * Anne || December 23 – 31 || bgcolor=#|Category 1 tropical cyclone || bgcolor=#|55 kn || bgcolor=#|980 hPa || || || ||
 * Bob || December 31 – January 12 || bgcolor=#|Category 3 severe tropical cyclone || bgcolor=#|85 kn || bgcolor=#|945 hPa || || || ||
 * Charles || February 13 – March 1 || bgcolor=#|Category 3 severe tropical cyclone || bgcolor=#|85 kn || bgcolor=#|945 hPa || || || ||
 * Diana || February 15 – 22 || bgcolor=#|Category 2 tropical cyclone || bgcolor=#|55 kn || bgcolor=#|980 hPa || || || ||
 * Ernie || February 17 – 23 || bgcolor=#|Category 2 tropical cyclone || bgcolor=#|55 kn || bgcolor=#|980 hPa || || || ||
 * Hal || April 13 – 22 || bgcolor=#|Category 3 severe tropical cyclone || bgcolor=#|70 kn || bgcolor=#|965 hPa || || || ||
 * Charles || February 13 – March 1 || bgcolor=#|Category 3 severe tropical cyclone || bgcolor=#|85 kn || bgcolor=#|945 hPa || || || ||
 * Diana || February 15 – 22 || bgcolor=#|Category 2 tropical cyclone || bgcolor=#|55 kn || bgcolor=#|980 hPa || || || ||
 * Ernie || February 17 – 23 || bgcolor=#|Category 2 tropical cyclone || bgcolor=#|55 kn || bgcolor=#|980 hPa || || || ||
 * Hal || April 13 – 22 || bgcolor=#|Category 3 severe tropical cyclone || bgcolor=#|70 kn || bgcolor=#|965 hPa || || || ||
 * Ernie || February 17 – 23 || bgcolor=#|Category 2 tropical cyclone || bgcolor=#|55 kn || bgcolor=#|980 hPa || || || ||
 * Hal || April 13 – 22 || bgcolor=#|Category 3 severe tropical cyclone || bgcolor=#|70 kn || bgcolor=#|965 hPa || || || ||
 * Hal || April 13 – 22 || bgcolor=#|Category 3 severe tropical cyclone || bgcolor=#|70 kn || bgcolor=#|965 hPa || || || ||
 * Hal || April 13 – 22 || bgcolor=#|Category 3 severe tropical cyclone || bgcolor=#|70 kn || bgcolor=#|965 hPa || || || ||