Intense rainfall and thunderstorms impacted New Caledonia early this morning, with more to come for other South Pacific islands to the east.
Flooding rainfall and intense thunderstorms in New Caledonia
The satellite imagery below shows an area of convergence into a low pressure trough moving over New Caledonia early on Wednesday, June 4. This convergence of moist east to northeast winds (to the east of the trough) and drier westerly winds (to the west of the trough) triggered these intense thunderstorms and heavy downpours over the French territory.
Video: satellite loop and detected lightning on Wednesday morning, June 4 over New Caledonia as seen on DTN’s Stormtracker.
According to Météo France Nouvelle-Calédonie, the heaviest falls were recorded within a period of six to 12 hours on the morning of Wednesday, June 4, including:
- 219mm at Poindimié
- 206mm at Yaté (including 99mm in one hour and 171mm in three hours)
- 167mm at Touho
- 124mm at Canala
The notable heavy rainfall totals exceeding 100mm were mostly located on the northeastern coast of Grande Terre, the main island. This is due to the mountain range that runs the length of the island, causing the moist Pacific Ocean winds to precipitate intensely.
Image: DTN MetStorm QPE showing estimated observed rainfall over New Caledonia during the 24 hours ending at 2pm NCT on Wednesday, June 4, 2025.
Thunderstorms affected the whole archipelago, with 22mm falling at Nouméa, the capital city. Strong wind gusts reaching 47 knots (87km/h) were also recorded at Nouméa and Phare Amedée, an offshore lighthouse island.
300,000 lightning strikes were also recorded within 500km of Nouméa over the past 36 hours, according to the DTN Total Lightning Network.
Flooding and thunderstorms coming for other South Pacific nations
The convergence line that impacted New Caledonia is starting to impact Vanuatu this afternoon. Less intense rainfall is expected over the volcanic archipelago, but severe thunderstorms could still deliver 30-50mm of rain in short periods of time this Wednesday afternoon and evening – possibly causing flash flooding and disruptions.
Image: In a region where radar coverage is sparse, the DTN Synthetic Radar and Total Lightning Network shows where adverse weather is starting to impact Vanuatu on the afternoon of Wednesday, June 4, 2025.
A more prolonged, but less intense, period of rainfall is expected for Fiji, lasting between Thursday morning and Friday afternoon. Tonga is forecast to receive more intense rainfall later on Friday and on Saturday morning.
Image: forecast accumulated rainfall across the South Pacific to 10pm AEST on Sunday, June 8.
Other South Pacific islands can also expect periods of rain between late this week and early next week. The convergence of winds is set to weaken as the week goes on, so the rainfall is not expected to be intense, but will be reminiscent of the wetter summer months.
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