Weekly Global Climate Pulse: Thursday, November 5, 2026

By Paul Harrison, Orbis Weather · Nov 5, 2026

At a glance

El Niño has reached record strength on some measures: Japan’s weather agency calls it the strongest on record since September, and Australia’s Bureau of Meteorology reports a record weekly index.

• ENSO: NOAA’s El Niño Advisory remains in force. NOAA’s preliminary Oceanic Niño Index for August–October 2026 is +2.5°C (+4.5°F).
• Oceans: Sea surface temperature for 60°S–60°N set a September record (Copernicus, October 12).
• Temperatures: September 2026 was the second-warmest September on record (Copernicus and NOAA). October figures are due November 6.
• Sea ice: Antarctic daily extent was at record lows for the time of year from October 2 (NSIDC, October 7).
• Drought: 49.5% of the contiguous US was in drought on the October 27 map, slightly less than a week earlier.
• Records: Carbon dioxide, methane and nitrous oxide reached record highs in 2025 (WMO, October 27). Hong Kong had its warmest October on record.

Data dates. New this week: NOAA’s November ONI and RONI update, the Hong Kong Observatory’s October report (November 3) and ASEAN haze outlooks (November 4). Latest available from earlier: NOAA ENSO discussion (October 8), NOAA weekly ENSO update (October 26), Bureau of Meteorology update (October 27), Copernicus September bulletin (October 12), NOAA NCEI September report (October 9), NSIDC September analysis (October 7) and the US Drought Monitor map released October 29. This week’s Drought Monitor map is due later on November 5.

El Niño and La Niña

El Niño is strong and still strengthening, and agencies expect it to peak around November or December. NOAA’s Climate Prediction Center (CPC) gives a greater than 83% chance of a strong-to-very strong El Niño through January–March 2027 (October 8 discussion).

Values are departures from each agency’s own baseline; RONI is now CPC’s official index, and the latest ONI and RONI values may be revised. JMA says the strongest El Niño conditions are “virtually certain (100%)” to continue until boreal winter; its September NINO.3 value beat the previous record of +3.6°C (+6.5°F) from December 1997. The WMO’s Global Seasonal Climate Update (October 21) forecasts a Niño 3.4 anomaly of about +3.8°C (+6.8°F) for November–January.

Indian Ocean Dipole: a positive event is underway. The Bureau of Meteorology’s index was +0.69°C (+1.24°F) for the week ending October 25, above the +0.4°C threshold for seven consecutive weeks, and is expected to return to neutral in early southern summer.

Oceans and global temperatures

The latest monthly data, for September 2026, show record ocean warmth in both the Copernicus and NOAA records, while global surface temperature ranked second behind September 2023.

Copernicus puts the 12 months to September at +1.50°C (+2.70°F) above 1850–1900. It also reports the Niño 3.4 region averaging 29.70°C (85.5°F) in September, an all-time high. NOAA says September was the warmest on record for the Arctic region, North America and Asia, and that 2026 is “very likely” to rank among the five warmest years. Europe was +1.54°C (+2.77°F) above 1991–2020, its third-warmest September (Copernicus).

Coral reefs: Hawaii has seen no evidence of widespread heat-stress bleaching this year, and NOAA’s outlook kept the islands at “watch” or no alert (The Garden Island, October 30). NOAA Coral Reef Watch has posted no new global bleaching statement since June, when it said the fourth global event likely ended in 2025.

Sea ice

Antarctic sea ice is running at record lows for the time of year, while Arctic ice ended its melt season low but well above the 2012 record. Neither NSIDC nor Copernicus has yet published October figures; the latest monthly data are for September.

The two sets of figures differ because they use different satellite datasets and baselines. NSIDC called its minimum and maximum figures “a preliminary announcement” and said the Antarctic maximum date is uncertain. In its October 7 analysis, NSIDC described Arctic freeze-up after the minimum as “rapid”.

Drought

US drought eased slightly in the West and Plains but worsened along the Lower Mississippi Valley and in the Southeast, on the map valid October 27 and released October 29. This week’s map is due later on November 5.

• Improved: much of New Mexico, Arizona and Nevada, the southern High Plains, Colorado, Texas and Oklahoma.
• Worsened: extreme to exceptional drought (D3–D4) now covers much of central and western Tennessee, Arkansas and Louisiana, and expanded in Missouri. Georgia, the Carolinas, southern Virginia and central Maine also degraded.
• Territories: St. John in the US Virgin Islands fell to exceptional drought, joining St. Thomas.

Drought.gov counts 93.1 million people and 43 states in drought on the same map.

Worldwide: Bolivia declared a national emergency on October 31 over drought and El Niño, with about 78,000 families affected (Al Jazeera, November 1). In England, parts of the south-west and south-east remain in severe drought, with reservoir storage 57.9% on October 27, despite the wettest week since October 2024 (Environment Agency, October 30). FEWS NET has high concern for below-average rain in Southern and East Africa through March 2027.

Records and milestones

The main record confirmed in the past fortnight is a new high for all three main long-lived greenhouse gases.

The WMO’s Ko Barrett summed up the bulletin as “Another year, another new record.” Whether October 2026 set a global record is not yet confirmed; Copernicus publishes its October figures on November 6.

What to watch

Next week brings the October global temperature figures and the WMO’s annual climate update at COP31 in Antalya, Türkiye (November 9–20).

NSIDC’s October analysis has no announced date; the September report appeared on October 7.

About this report

The Weekly Global Climate Pulse tracks slow-moving climate indicators rather than day-to-day weather. Agencies use different baselines: 1991–2020 is the current standard for “normal”, 1850–1900 approximates pre-industrial conditions and is used for the Paris Agreement’s 1.5°C goal, and NSIDC keeps 1981–2010 for sea ice. Anomalies against different baselines are not directly comparable. Most indicators update monthly, and the latest ONI, RONI and sea ice figures are preliminary and may be revised.

• Anomaly: the difference from the average for the same period over a baseline.
• ENSO: El Niño–Southern Oscillation, the cycle of warming and cooling in the tropical Pacific.
• Niño-3.4: a central-eastern Pacific region whose sea temperature is the main El Niño yardstick; ONI is its three-month average.
• Indian Ocean Dipole (IOD): the temperature difference between the western and eastern tropical Indian Ocean.
• Sea ice extent: the area of ocean that satellites classify as ice-covered, a different measure from ice volume.

Frequently asked questions

Is this the strongest El Niño on record? On some measures, yes. JMA’s September NINO.3 value and the Bureau of Meteorology’s weekly relative index are records, but the Bureau notes monthly values remain below previous records. NOAA gives an 83% chance that a three-month RONI reaches “historic” strength in October–December.

When will El Niño peak? The Bureau of Meteorology says all models forecast a peak around November or December. The WMO also expects warming to peak around December 2026, and NOAA expects El Niño to last through January–March 2027.

Was October 2026 the warmest October on record worldwide? No agency has confirmed it yet. Copernicus releases its October figures on November 6, and NOAA’s global report follows later.

Why do NSIDC and Copernicus give different sea ice numbers? They process satellite data differently and compare against different baselines, so totals and ranks differ. Both agree that the 2026 Antarctic winter maximum was the third lowest on record.

Is US drought getting better? It is mixed. The share of the contiguous US in drought dipped slightly in the latest map, but the area in exceptional drought grew, and conditions worsened from Missouri to Louisiana and in the Southeast.

Sources

• NOAA CPC ENSO Diagnostic Discussion, October 8, 2026
• NOAA CPC weekly ENSO update (PDF), October 26, 2026
• NOAA CPC Oceanic Niño Index and Relative ONI, November 2026 update
• JMA El Niño Outlook, October 9, 2026
• Bureau of Meteorology Climate Driver Update, October 27, 2026
• WMO Global Seasonal Climate Update, Nov–Jan, October 21, 2026
• Copernicus: second-warmest September, October 12, 2026
• Copernicus surface air temperature, September 2026, October 2026
• Copernicus sea ice cover, September 2026, October 2026
• NOAA NCEI global climate, September 2026, October 9, 2026
• The Garden Island: Hawaii coral bleaching, October 30, 2026
• NOAA Coral Reef Watch, June 2, 2026 (latest statement)
• NSIDC: Stranger Things in the 2026 Arctic, October 7, 2026
• NSIDC: Arctic sea ice minimum ties tenth lowest, September 23, 2026
• US Drought Monitor summary and category table (PDF), October 29, 2026 (map valid October 27)
• Drought.gov national summary, data valid October 27, 2026
• Al Jazeera: Bolivia declares state of emergency, November 1, 2026
• Environment Agency: dry weather and drought in England, 23 to 29 October, October 30, 2026
• FEWS NET: El Niño 2026–2027, October 27–November 4, 2026 items
• ASEAN Specialised Meteorological Centre, November 4, 2026
• WMO: greenhouse gas levels reach record high, October 27, 2026
• Hong Kong Observatory: October 2026 weather, November 3, 2026
• WMO activities during COP31, November 4, 2026
• ECMWF and Copernicus at COP31, November 3, 2026