Moving generally east, development was initially slow and the system finally reached cyclone strength—having gale-force winds—on December 30.

The newly christened Tropical Cyclone Ula turned sharply south and rapidly intensified, attaining hurricane strength the following day.

After turning back to the southwest, it achieved its peak intensity as a Category 4 on the Australian scale with winds of 185 km/h (115 mph) on January 10.

Throughout its existence, Ula affected several nations but its effects were largely limited, with only localized areas reporting damage.

[6] Early in the storm's existence, Ula produced winds up to 100 km/h (62 mph) across Tuvalu, uprooting trees and leaving 40 homes and 10 businesses damaged, some beyond repair[7][8] Thirty families required evacuation.

[10] On January 1, Tongan Prime Minister ʻAkilisi Pōhiva preemptively declared a state of emergency for the Vavaʻu and Haʻapai islands.

[12] Strong winds up to 150 km/h (93 mph) downed trees, power lines, and tore roofs from homes, with Vava'u suffering the brunt of the damage.

Officials across the small islands advised residents to move to higher ground and seek shelter in sturdy buildings.

[18] Crops also sustained significant damage,[16] with 50 percent lost across the Lau Islands,[19] prompting the Fijian Government to provide a month's-worth of food rations to residents across 13 villages.

[20] General relief supplies, including disaster kits, medicine, and water purifying tablets, were also distributed to Ono-i-Lau, Ogea, Fulaga and Kabara.