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Island Climate Update

A summary of the climate across the islands of Te Moana-niu-a-kiwa (Pacific Ocean), with an outlook for the coming months.

El Niño continued during February and has around an 80% chance of persisting through April. However, ENSO neutral conditions are favoured to develop during May-July 2024.

The monthly NINO3.4 Index anomaly (in the centralequatorial Pacific) at the end of February was +1.55˚C, within the range of a strong El Niño (classified when the NINO3.4 Index is greater than +1.5˚C). Although the current El Niño event is past its peak oceanic intensity, atmospheric patterns will likely continue to show El Niño-like tendencies in the months ahead.

TheSouthern Oscillation Index (SOI) was in the El Niño range during February (-1.1) and the neutral range during December-February (-0.4). This suggests that El Niño’s reflection in the atmosphere has been atypical, particularly considering the oceanic intensity.

Trade wind strength was was slightly below normal across most of the equatorial Pacific during February and greatly reduced from normal in the off-equatorial South Pacific, where winds blew from the west.

During mid-March, an area of enhanced trade winds is forecast in the west-central equatorial Pacific, a reversal of February’s pattern and the one that dominated over recent months.

In February, the subsurface equatorial Pacific was cooler than average below 100 m depth across most of the basin. Above average temperatures were confined to the upper 50-100 m. Upper-oceanic heat content returned to near normal values in the equatorial Pacific aside from the far eastern part of the Pacific, suggesting that the ‘cool pool’ of sub-surface water had significantly eroded warmth associated with El Niño.

A marine heatwave remains active between Vanuatu and Fiji, as well as island groups farther east including the northern Cook Islands.

During mid-March, a pulse of the Madden-Julian Oscillation may increase the chance for tropical cyclone development between Vanuatu and the Coral Sea. With an El Niño event ongoing, all met services should remain vigilant.

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Island Climate Update - March 2024 [PDF 2.28 MB]

Additional resources

Additional regional and country situation summary and forecast information can be obtained below. Current rainfall accumulation status and other derived summary information are updated on a daily basis (with a 2-day lag), with seasonal forecast information updated once per month.

 

About the Island Climate Update

NIWA is the Network co-lead for the WMO RA V Regional Climate Centre Node on Long Range Forecast and consortium member for nodes on Climate Monitoring, Operational Data Services and Training.

Development and production of the ICU is supported by NIWA Strategic Science Investment Funding under contract PRAS2301. The Island Climate Update bulletin and associated video and products are prepared as soon as possible at the start of each month. Delays in data availability occasionally arise. While every effort is made to verify the data, NIWA does not guarantee the accuracy and reliability of the analysis and forecast information presented and accepts no liability for any losses incurred through the use of this bulletin and its contents. The contents of this bulletin and all associated products produced by the Island Climate Update may be freely disseminated provided the source is acknowledged.

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Issues

The NINO3.4 Index anomaly (in the central Pacific) during February was -0.60˚C, near the La Niña threshold. The monthly Southern Oscillation Index (SOI) was +0.7 and the three-month average SOI was +0.8, the latter near the La Niña threshold.
The NINO3.4 Index anomaly (in the central Pacific) during January was -0.70˚C, in the La Niña range. The monthly SOI was +0.3 and the three-month average SOI was +0.9, the latter near the La Niña threshold.
The NINO3.4 Index anomaly (in the central equatorial Pacific) over the last month was -0.68˚C, near the La Niña threshold. The monthly Southern Oscillation Index (SOI) was +1.3 and the three-month average SOI was +1.0, both in the La Niña range.
The NINO3.4 Index anomaly (in the central Pacific) during November (through the 28th) was -0.59˚C and the Southern Oscillation Index (SOI) was +1.1, both near the La Niña threshold. The three month average SOI was +0.9.
The NINO3.4 Index anomaly (in the central Pacific) during October was -0.59˚C. The latest weekly value was -0.80˚C, continuing the trend towards La Niña. The Southern Oscillation Index (SOI) was +0.7 during October and August-October, on the La Niña side of neutral. Overall, this represented an ocean-atmosphere system that was on the verge of La Niña conditions.
The NINO3.4 Index anomaly (in the central Pacific) during September was -0.23˚C. Compared to this time last year, conditions are about 0.5˚C warmer. The Southern Oscillation Index (SOI) was +0.8 during September, on the La Niña side of neutral. Notably, the three-month average SOI was +1.0, in La Niña territory.
The NINO3.4 Index anomaly (in the central Pacific) during August was -0.17 ̊C. The Southern Oscillation Index was +0.5. While both remained in neutral territory, other indicators trended toward La Niña.
The NINO3.4 Index anomaly (in the central Pacific) during July was 0.08 ̊C. The Southern Oscillation Index was +1.7, firmly in La Niña territory.
The NINO3.4 Index anomaly (in the central Pacific) during June was 0.18 ̊C, the first time it has been positive since July 2020. The Southern Oscillation Index was +0.4, in the ENSO neutral range.
The NINO3.4 Index anomaly (in the central Pacific) during May (through the 30th) was -0.11˚C, the smallest anomaly since July 2020. The Southern Oscillation Index (SOI) was +0.5, in the ENSO neutral range.
The NINO3.4 Index anomaly (in the central Pacific) during April was -0.30⁰C and the SOI (Southern Oscillation Index) was +0.3, both within the neutral range.
The NINO3.4 Index anomaly (in the central Pacific) during March was -0.44˚C. This marked the first time since August 2020 that SSTs in this region were in the neutral range. The SOI value for March was +0.1 (in the neutral range).
The NINO3.4 Index anomaly (in the central Pacific) during January was -0.68˚C, entering ENSO “cool neutral” territory (-0.5 to -0.69˚C) for the first time since August 2020.
The NINO3.4 Index anomaly (in the central Pacific) during January was 0.81˚C, increasing slightly compared to the previous month.
The NINO3.4 Index anomaly (in the central Pacific) for the last month (through the 3 rd of January) was 0.84˚C, increasing from 1.03˚C from last month.
During November, the NINO3.4 Index anomaly (central Pacific) was 1.02˚C. The NINO 1+2 Index (eastern Pacific) was 0.54 C. The most unusually cool SSTs have now shifted into the central Pacific.
During October, the NINO3.4 Index anomaly (central Pacific) was 0.86˚C. The NINO 1+2 Index (eastern Pacific) was 0.56 C. Upper oceanic heat content continued to decrease in the east central part of the Pacific basin.
During September, the NINO3.4 Index anomaly (central Pacific) was 0.71˚C. The NINO 1+2 Index (eastern Pacific) was 0.76 C.
During August, the NINO3.4 Index anomaly (in the central Pacific) was 0.42˚ C. The NINO 1+2 Index (eastern Pacific) was 0.85 C.
During July, the NINO3.4 Index anomaly (in the central Pacific) was +0.04˚C. The NINO 1+2 Index (eastern Pacific) was 0.72 C, decreasing from 0.57 C in June.
During June, the NINO3.4 Index anomaly (in the central Pacific) was 0.12˚C. Upper oceanic heat content decreased notably across the east central equatorial Pacific.
During May the NINO3.4 Index anomaly (in the central Pacific) for May was +0.01˚C, with upper oceanic heat content continuing to decrease across the equatorial Pacific.
El Niño Southern Oscillation (ENSO) neutral conditions continued during April 2020. The Southern Oscillation Index (SOI) was +0.1.
El Niño Southern Oscillation (ENSO) neutral conditions continued during March 2020. The Southern Oscillation Index (SOI) was 0.5.

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