Oceania experienced pronounced warmth across its major landmasses during the month, driven by a powerful atmospheric combination…
Top 5 Countries: Australia, New Zealand, Papua New Guinea, Fiji, and Solomon Islands
Summary
Oceania experienced pronounced warmth across its major landmasses during the month, driven by a powerful atmospheric combination. While larger continental areas faced intense heat and early snowmelt in alpine regions, several Pacific island nations recorded conditions cooler than the long-term baseline. A strong El Niño forecast to peak at Very Strong in October to December, operating alongside a positive Indian Ocean Dipole, continues to steer these regional weather patterns. Looking ahead, above-average temperatures are likely to persist across much of the continent into late spring.
This month in numbers
Oceania recorded a 1-month average temperature anomaly of +1.80°C above the 1961-1990 baseline. Over broader multi-month periods, the 3-month anomaly reached +1.32°C, while the 12-month rolling temperature figure stood at +0.98°C. On a global scale, where 8 of the top 10 warmest anomalies were concentrated in US states, Oceania presented a split pattern, with heat over continental areas balanced by cooler anomalies across several South Pacific island nations.
Hottest & coolest countries
Warming was most pronounced in Australia, where the monthly anomaly climbed to +2.14°C above baseline. Higher temperatures were also observed in New Zealand at +0.78°C and Papua New Guinea at +0.63°C. In contrast, several island nations recorded below-average temperatures, led by Vanuatu at -0.59°C, followed by New Caledonia and Fiji, which both sat at -0.33°C.
What's driving change?
The primary climate engine across the region is ENSO, with NOAA data confirming a strong El Niño in place at a relative anomaly of +1.69°C on our tracker at ENSO. This tropical Pacific warming is operating alongside a positive Indian Ocean Dipole, creating atmospheric pressure shifts that suppress cloud cover and rain over southern landmasses. Because areas, interior regions heated rapidly under , accelerating seasonal shifts and soil drying.
Looking ahead
Seasonal outlooks indicate that widespread above-average temperatures and lingering rainfall deficits are likely to persist across major parts of Australia and the western Pacific through late spring and early summer.
Precipitation, Sunshine, Frost and Snow are converted to standard deviations from their own average so they can share an axis with Temperature anomalies.
Metric
Insight
Temperature
10-Yr AverageActual Year
Climate History
49 of 49 events
1912Volcanic
Novarupta (Katmai) eruption
The largest volcanic eruption anywhere in the world in the 20th century - 13 km3 of magma, about thirty times the 1980 Mount St. Helens eruption - at Novarupta in Alaska on 6-8 June 1912. Ash reached 100,000 ft and cooled the Northern Hemisphere by roughly 0.3°C over 1912-13. Unlike a tropical eruption such as Pinatubo, a high-latitude eruption's haze stays in its own hemisphere, so it did little to the Southern Hemisphere.
After the Second World War, coal and oil use grew rapidly across Europe, North America and the Soviet Union. Global sulphur dioxide emissions rose from about 30 to about 130 million tonnes a year by 1980, and the sulphate haze they formed masked part of the greenhouse warming underneath - the effect known as 'global dimming'.
One of the strongest La Niñas since instrument-based ENSO records begin in 1950, and part of a run of cool Pacific years through the mid-1950s. La Niña cools global temperatures slightly for a year or two while it lasts, and shifts rainfall patterns worldwide.
Charles David Keeling begins continuous measurements of atmospheric CO₂ at Mauna Loa Observatory in Hawaii, starting at about 315 ppm. The record has risen every year since and is now the longest unbroken direct measurement of CO₂ anywhere - the 'Keeling Curve'.
On 10 April 1968 Cyclone Giselle met a southerly storm over Wellington, bringing the strongest winds ever recorded in the city. The inter-island ferry Wahine was driven onto a reef at the harbour entrance and capsized; 53 people died, New Zealand's worst modern maritime disaster.
One of the strongest El Niños on record. It contributed to failed grain harvests in the Soviet Union and elsewhere in 1972, and to a sharp rise in world food prices - an early sign of how far ENSO's reach extends.
In the La Niña year of 1974, the remnants of Cyclone Wanda stalled over south-east Queensland. On 26 January Brisbane had 314 mm of rain, its wettest day in 87 years, and the river peaked at 5.45 m in the city - its largest flood since 1893. 16 people died and 8,000 homes were destroyed. 1974 is Australia's coldest year in this site's 1950-2025 record.
The Pacific Decadal Oscillation - a slow natural cycle in North Pacific sea temperatures - switches from its cool to its warm phase in 1976-77. The change was abrupt enough to be called the 1976-77 Pacific Climate Shift: it warmed Alaska and the west coast of North America, and reorganised North Pacific fisheries.
Global sulphur dioxide emissions peak at about 130 million tonnes a year, then begin a long decline as Europe, North America and Japan clean up their air. As the aerosol mask thins, the rate of global warming picks up through the 1980s.
A sulphur-rich eruption in Mexico whose aerosol cloud stayed in the stratosphere for more than two years, cooling the Northern Hemisphere by about 0.2°C.
The strongest El Niño since 1950 on NOAA's Relative Oceanic Niño Index, which strips out the background warming of the tropical oceans before ranking events. On the older index that leaves that warming in, 2015-16 comes out on top instead.
British Antarctic Survey scientists Joe Farman, Brian Gardiner and Jon Shanklin publish their Halley and Faraday measurements on 16 May 1985, showing October ozone over Antarctica had fallen to about two-thirds of earlier decades. The cause is traced to chlorofluorocarbons, and the finding triggers the fastest international environmental response on record.
Signed in 1987 to phase out ozone-depleting chlorofluorocarbons, the Montreal Protocol turned out to be one of the most consequential climate treaties ever agreed. CFCs are potent greenhouse gases in their own right, and NOAA estimates the Protocol prevented up to 2°C of warming by 2100 - around 1°C from the emissions avoided, and up to 1°C more by sparing forests and other carbon sinks from increased ultraviolet radiation.
Atmospheric CO₂ passes 350 ppm. In the same year James Hansen told a US Senate committee that global warming was already detectable, the moment it entered mainstream politics. Twenty years later, in 2008, Hansen proposed 350 ppm as the safe upper limit - a level the world had already left behind.
One of the strongest La Niñas on record, arriving straight after the 1986-87 El Niño - a swing from one extreme of the Pacific cycle to the other in barely a year.
In March 1988 the remains of Cyclone Bola sat over the east of the North Island for three days, dropping more than 900 mm of rain on the Gisborne ranges, with 514 mm in a single day. Floods and landslides stripped hill-country farms and cut off Gisborne; it remains one of New Zealand's most damaging storms.
Daytime warming catches up with the night-led pattern
Across 1961-90, 81% of the world's land saw nights warming faster than days. Across 1991-2020 the pattern reversed: 70% saw days warming faster, as the industrial haze that had been dimming daytime sunshine was cleaned up. The study compares two fixed thirty-year windows; measured as a turning point, this site's own global series turns around 1982.
Mount Pinatubo in the Philippines erupts in June 1991, the largest eruption since 1912. Its sulphate haze cooled global surface temperature by about 0.5°C in 1992 and reduced rainfall over land for about two years, before the warming trend resumed.
Atlantic Multidecadal Oscillation flips to a warm phase
The Atlantic Multidecadal Oscillation - a slow natural cycle in North Atlantic sea temperatures, roughly 60-70 years long - flips to its warm phase in 1995. Warm phases are linked to more active Atlantic hurricane seasons, wetter summers in parts of north-west Europe and more frequent drought in the central and western United States.
One of the strongest El Niños on record, and the one the textbook El Niño pattern is usually drawn from. It pushed 1998 to what was then the warmest year ever measured, and set off the first global-scale coral bleaching event.
The 1997-98 El Niño left much of Papua New Guinea with little or no rain from early 1997, one of the most severe droughts in a century. Repeated frosts above 2,200 m in Enga and the Southern and Western Highlands killed the sweet potato gardens people live on, and more than half a million people were seriously short of food.
A strong La Niña that ran for three winters after the record 1997-98 El Niño, peaking at an ONI of -1.53. It pulled global temperatures back below 1998's record for several years, and brought the usual La Niña pattern of dry winters across the southern United States and wet years in Australia and Indonesia.
Pacific Decadal Oscillation flips back to a cool phase
The Pacific Decadal Oscillation - a slow natural cycle in North Pacific sea temperatures - flips back to its cool phase around 1998-99. The cool phase that followed is one reason global surface warming appeared to slow in the 2000s, as more heat went into the deep Pacific.
The longest and most severe drought on record in south-east Australia and the Murray-Darling Basin, the country's largest river system. It brought water restrictions to most major cities and devastated irrigated farming.
Cyclone Erica struck New Caledonia on 13 March 2003, the worst cyclone there since Beti in 1996. It tore roofs from houses along the west coast, brought down trees, power and phone lines, and left two people dead, a hundred injured and about a thousand homeless.
A moderate-to-strong El Niño that peaked around the turn of 2009-10. It helped make 2010 one of the warmest years on record at the time, and was followed straight away by the strong La Niña of 2010-12.
On 7 February 2009, after a heatwave that took Melbourne to 46°C, hundreds of bushfires swept across Victoria. 173 people died and more than 2,000 homes were destroyed - Australia's deadliest bushfire disaster.
Globally, heatwave days have roughly doubled each decade since 2010 - from an average of 5.3 a year in the 2000s to 11.5 in the 2010s and 18.9 so far in the 2020s, weighted by land area across 169 countries. El Niño has not become more extreme. The whole temperature distribution has shifted upwards, so the same natural El Niño and La Niña cycle now pushes far more days over fixed extreme-heat thresholds.
A strong double-winter La Niña peaking at an ONI of -1.57. It gave Australia its wettest two years on record and the Queensland floods of 2010-11 - so much rain fell on land that global sea level briefly dropped in 2011 - and it fed drought in the Horn of Africa and in Texas.
Atmospheric CO₂ passes 400 ppm at Mauna Loa on 9 May 2013 - a level the planet had not seen for 3-5 million years, since the Pliocene, when sea levels were many metres higher.
In early April 2014 a slow tropical depression, which later became Cyclone Ita, dropped days of heavy rain on Guadalcanal. The Mataniko River burst its banks through Honiara on 3 April; 22 people died, more than 50,000 were affected and about 10,000 sheltered in evacuation centres.
The strongest El Niño on record by raw ONI - though on NOAA's newer RONI index, which strips out background tropical-ocean warming, 1982-83 ranks slightly ahead instead. 2016 became the hottest year on record at that time (+1.0°C above pre-industrial).
The eleven warmest years ever measured are 2015 through 2025, an unbroken run - the longest sustained stretch of record warmth in the 176-year instrumental record. 2023 and 2024 each broke the previous record in turn.
Category 5 Cyclone Pam crossed Vanuatu on 13 March 2015, affecting up to 90% of the country's buildings and causing about US$449 million of damage. Early warnings and traditional shelters kept the death toll to 11 people, remarkably low for a storm of its strength.
Cyclone Winston struck Fiji on 20 February 2016 with winds of up to 185 mph (about 295 km/h), the strongest cyclone recorded in the Southern Hemisphere and the first Category 5 storm to make landfall in Fiji. It killed 44 people and destroyed tens of thousands of homes.
May to September 2016 was Australia's wettest on record, with each of the five months among the ten wettest in more than a century. A strong negative Indian Ocean Dipole - warm water off north-west Australia feeding moisture across the continent - drove much of it; on this site's rainfall record July-September 2016 was Australia's wettest since 1950.
2019 was Australia's warmest and driest year on record - 1.52°C above the 1961-1990 average, with rainfall about 40% below - and the first year with both records at once. A strong, long-lived positive Indian Ocean Dipole affected Australia from May to the end of the year, and a rare spring breakdown of the southern polar vortex cut rainfall further; on this site's record September-November 2019 was Australia's driest since 1950. December's fire weather was the worst on record, and destructive bushfires burned in every state through the 2019-20 summer.
Global fossil CO₂ emissions fell about 5.8% in 2020, from 37.0 to 34.8 billion tonnes, yet atmospheric CO₂ still rose 2.5 ppm - the dip barely registers in the atmospheric record. Emissions were back to pre-pandemic levels by 2022.
New international shipping rules cut the sulphur allowed in ship fuel from 3.5% to 0.5% almost overnight, removing about 8 million tonnes of sulphur dioxide a year. With less sulphate haze over the oceans, it may have added around 0.1°C of warming by 2023-24.
Three consecutive La Niña winters - a 'triple dip', which has happened only a handful of times since 1950 - peaking at an ONI of -1.11. It held global temperatures slightly below where the warming trend would otherwise have put them, and coincided with five failed rainy seasons in a row in the Horn of Africa and severe flooding in eastern Australia in 2022.
In February and March 2022 extreme rain flooded south-east Queensland and northern New South Wales. At Lismore the Wilsons River peaked at 14.4 m - about 2 m above any flood in records going back to 1887 - and 2022 went on to be Lismore's wettest year on record.
2022 was New Zealand's warmest year on record - 13.76°C, 1.15°C above the 1981-2010 average in NIWA's series from 1909 - and its 8th most unusually wet since 1960. NIWA links it to the third year of La Niña, a record positive Southern Annular Mode (positive 76.2% of the year, the most since at least 1979), a negative Indian Ocean Dipole and coastal seas above average every month. Winter was the wettest and warmest on record, and an August atmospheric river flooded Nelson, bringing a state of emergency.
A strong El Niño arriving on top of long-term greenhouse warming, with the cut in shipping sulphur from the 2020 fuel rule adding a little more. Together they produced the record global temperatures of 2023 and 2024.
Two disasters in three weeks. On 27 January 2023 Auckland had its wettest day on record - 261 mm in 18 hours - and four people died. Then on 12-14 February Cyclone Gabrielle tore down the east coast of the North Island, killing 11 and prompting a national state of emergency.
Two Category 4 cyclones, Judy and Kevin, struck Vanuatu within about 48 hours in early March 2023, Judy making landfall on Efate near Port Vila. About 197,000 people - roughly two-thirds of the population - were affected.
Warm Spell Duration Index (WSDI) - days in a 6+ day run above the local 90th-percentile temperature for that time of year. Equal-weight mean across 2 countries.
Heatwave days per year2019 (Record)10-yr avg
Data: World Bank Climate Change Knowledge Portal (ERA5-derived), aggregated by 4BYO across member countries. Refreshed roughly 1-2x/year, ~7-8 months behind present.
Source: Copernicus ERA5 (countries) · NOAA Climate at a Glance (continents, US states & climate regions) · Met Office (UK) · GPCC (rainfall, snow) · World Bank CCKP (frost). Anomalies are vs the 1961–1990 baseline. See methodology.
4byo continent aggregate · equal-weight mean of member country monthly absolute temperatures (OWID/CRU TS); precipitation: GPCC (DWD). - Anomalies vs 1901-2000 mean
Oceania has both a clear warm/cold cycle (±6.8°C) and a wet/dry cycle (4× wet:dry ratio). Both sides of the annual rhythm are shown below.
Shifting summer
9 Days Longer
Warm Season
1940–1969 Baseline: 5 Oct → 20 Apr · 197 days
2016–2025 Now: 28 Sep → 23 Apr · 206 days
−7d+3d
JanJFebFMarMAprAMayMJunJJulJAugASepSOctONovNDecD
Spr 7 Days EarlierAut 3 Days Later
Shifting wet season
9 Days Shorter
Wet Season
1891–1920 Baseline: 22 Dec → 14 Apr · 113 days
2016–2025 Now: 17 Dec → 31 Mar · 104 days
−5d−14d
JanJFebFMarMAprAMayMJunJJulJAugASepSOctONovNDecD
Onset 5 Days EarlierEnd 14 Days Earlier
+2.8% annual rain
baseline avgrecent avgClickTap for decades
Wet-season onset
22 Dec→17 Dec
5 Days Earlier
When 25% of annual rain has fallen
Wet-season end
14 Apr→31 Mar
14 Days Earlier
When 75% of annual rain has fallen
Peak-rain month
Jan→Jan
Unchanged
Wet months: 4 → 5
1891–19202016–2025Wet-month threshold (42 mm)
Monthly precipitation climatology. A “wet month” exceeds the baseline monthly mean (dashed gold line). Biggest month-to-month shift: Mar (+9 mm, +14%).
4byo continent aggregate · OWID/CRU TS country monthly temperatures & precipitation: GPCC (DWD). Baseline: first 30 yrs on record. Recent: last 10 yrs on record.
Live GDACS alerts in Oceania - Red (Major), Orange (Severe) or Green (Moderate) - and the long-term record of weather and climate disasters.
Live Alerts
Loading…
Alerts, Last 12 Months
Major
0
0.8 a year since 2021
Severe
0
None since 2021
Moderate
1,527
Weather Disasters, 2025
Disasters
6
11 a year, 2016-2025
Deaths
29
102 a year, 2016-2025
Weather Disasters, 2016-2025
Most Frequent
Storms & Cyclones
51 of 112 disasters
Deadliest
Landslide
747 of 1,023 deaths
Disasters: EM-DAT, CRED / UCLouvain, via Our World in Data - 10+ deaths, 100+ people affected, or a declared emergency or call for international help. Alerts: GDACS.
The natural climate patterns that measurably shape seasonal temperature or rainfall in Oceania, from this site’s own data since 1950 - long-term trends removed, and ENSO’s share taken out before scoring the others, so each is credited only for what it adds.
El Niño / La Niña (ENSO)moderate link
The tropical Pacific’s warm and cool swings - the biggest natural driver of year-to-year climate.
Now: El Niño (strong) · RONI +1.7°C(Jul-Sep 2026)
Forecast - 100% very strong at peak, Sep-Nov, then neutral by Apr-Jun 2027 (NOAA). La Niña from Sep 2027 in SNU’s AI model.
A moderate or strong link for 100% of the places in this group.
Every figure on this page is sourced from official, openly published climate datasets. Anomalies are calculated against the 1961–1990 baseline (temperature) and 1991–2020 (rainfall, sunshine, frost) - see the Methodology & Sources page for the complete dataset list and update calendar.
Oceania is warming in line with the rest of the world. The page above shows the latest monthly temperature anomaly versus the 1961-1990 baseline, the long-term annual trend, and the region's rank in the historical record. The headline panel also shows the long-term trend rate per decade and the warmest and coolest years on file.
Which climate drivers affect the weather in Oceania?
Measured from seasonal temperature and rainfall in Oceania since 1950, with the long-term warming trend removed (and ENSO's own share removed before scoring the other drivers), the climate drivers with a clear effect here are: El Niño / La Niña (ENSO) - a moderate or strong link for 100% of the places in this group; the Indian Ocean Dipole (IOD) - a moderate or strong link for 100% of the places in this group. Their current state is shown in the Climate Drivers section of this page.
What extreme weather affects Oceania?
In 2025, the latest complete year, the international disaster database EM-DAT recorded 6 weather and climate disasters in Oceania, against an average of 11 a year in 2016-2025, with 29 deaths. Over those ten years the most frequent type was storms & cyclones (51 of 112) and the deadliest landslide. GDACS, the UN and European Commission's disaster alert system, issued 0 Major (Red) and 0 Severe (Orange) alerts for Oceania in the last 12 months. Live alerts are on this page and on the Extreme Weather tracker.
Where does the climate data for Oceania come from?
Climate data for Oceania comes from Our World in Data, sourcing Copernicus ERA5 and HadCRUT5 (national temperature anomaly) and the Global Carbon Project via Our World in Data (CO₂ emissions), refreshed every month, when the upstream temperature and rainfall data are refreshed.
What is the climate baseline used on this page?
Anomalies on this page are calculated against the 1961-1990 climatological baseline, which is the standard reference period used by the Met Office, NOAA, IPCC and most national climate services. Some panels also show the source-native 1901-2000 (NOAA) or 1991-2020 (WMO) baselines for verification. See Methodology & Sources for the full reference.
Which areas does the Oceania climate data cover?
The Oceania climate profile covers Australia, New Zealand, Papua New Guinea, Fiji and surrounding areas. Australia, New Zealand and the Pacific - continental temperature trends
How often is the Oceania climate update refreshed?
The Oceania climate update is refreshed monthly, typically a few days after the previous month closes and the upstream provider (Met Office HadUK-Grid, NOAA Climate at a Glance, Copernicus ERA5 or the Global Carbon Project) publishes its update. See the Climate Rankings for cross-region comparisons.
What counts as a Heatwave Day on the Oceania climate page?
Heatwave Days use the Warm Spell Duration Index (WSDI) - the WMO/ETCCDI-standard heatwave measure: days that are part of a run of 6 or more consecutive days above the local 90th-percentile temperature for that calendar day. The 90th-percentile threshold varies by time of year (a hot day in January is judged differently to one in July) but is fixed to the 1961-1990 baseline for every year shown - it does not shift as the climate warms, which is why Heatwave Days trend upward over time.
Does the Oceania climate page include frost and snow data?
Yes. Frost Days (days with a minimum temperature below 0°C, World Bank CCKP) and snow water-equivalent (GPCC) are shown alongside temperature and precipitation, each measured against the 1961-1990 baseline where a like-for-like historical comparison is available.
What major climate events has Oceania experienced?
Major climate events in Oceania include The Wahine storm, 1968; Cyclone Bola, 1988; Australia's Millennium Drought (2001-2009); Black Saturday, 2009; Cyclone Pam, 2015; Australia's wettest May-September, 2016; The eastern Australia floods of 2022; Cyclone Gabrielle and the Auckland floods, 2023. The Climate History panel on this page lists 49 sourced events and pattern shifts relevant to Oceania, the earliest from 1912 - 16 about Oceania itself and the rest global context such as volcanic eruptions and El Niño events. Each entry carries its own sources and can be searched, filtered to local events or by category, and sorted by date; scrolling the list moves a cursor across the chart above so you can see where each event falls in the record.
Where does the Climate History list for Oceania come from, and how is it checked?
It is a hand-reviewed register, not an automatic feed. Every entry is sourced, and each one records how it was verified - against this site's own data series, against a peer-reviewed paper, or against the public record of the event. The rest give global or national context shared with wider pages. Where a figure is narrower than it first appears, or a famous claim does not hold locally, the entry says so.
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