The world’s oceans have set a temperature record four months running, NOAA data show

With El Niño conditions in the Pacific, every month from June to September 2026 was the warmest on record for global sea surfaces in NOAA’s dataset — and September was the second-warmest September for the planet as a whole.

Noodle News data desk · reading time ~3 min

consecutive months of record ocean warmth, June to September 2026

1.33°C

September 2026 global anomaly against the 20th-century average

2nd

warmest September since 1850, behind only 2023

What the data shows

The ocean overtook 2023 in June and has stayed ahead

Global ocean surface temperature in September 2026 was 1.10°C above its 20th-century average, a record for the month and the fourth record month in a row, according to the US National Oceanic and Atmospheric Administration (NOAA).¹ NOAA attributes record warmth across the central and eastern tropical Pacific to persistent El Niño conditions, which it says contributed significantly to the high global ocean figures.¹

The year did not start that way. In January 2026 the ocean anomaly was 0.81°C, well below the same month in 2024. It rose almost every month from there. In June it passed the previous record, set in 2023, by 0.04°C, and by September the margin had grown to 0.08°C.²

Exhibit 01

Ocean temperature by month: 2026 has run above every earlier year since June

Source: NOAA NCEI Climate at a Glance, global ocean surface temperature anomaly, °C against the 1901–2000 average. Data retrieved 10 Oct 2026; recent months are provisional and are revised as late observations arrive.²

Key finding. June, July, August and September 2026 each beat the previous record for their month, set in 2023, by between 0.03°C and 0.08°C.²

A second dataset points the same way for August. The EU’s Copernicus Climate Change Service found August 2026 sea surface temperatures between 60°S and 60°N averaged 21.07°C, the highest August on record, though it noted that other datasets did not rank the month first.³

Land and sea together

September: second only to 2023

Combining land and ocean, September 2026 was 1.33°C above the 20th-century average — the second-warmest September in records going back to 1850, 0.07°C behind September 2023 and 0.21°C warmer than last September.¹ Land alone ranked third, behind 2023 and 2024. NOAA recorded the warmest September on record for the Arctic region, North America and Asia.¹

Exhibit 02

September global temperature anomaly, 2015 to 2026

Source: NOAA NCEI Climate at a Glance, global land and ocean, September, °C against the 1901–2000 average. The baseline is the 20th-century mean, not pre-industrial; the figures are not comparable with the 1.5°C Paris threshold.²

The year so far

Second behind 2024, after a cooler first half

January to September 2026 averaged 1.17°C above the 20th-century mean, the second-highest on record behind 2024 at 1.24°C.¹² NOAA says it is very likely 2026 will finish among the five warmest years, with the second-warmest the most probable outcome. That is NOAA’s assessment, not a measured result, and the year has three months to run.¹

Exhibit 03

The six warmest January-to-September periods since 2010

Source: NOAA NCEI Climate at a Glance, global land and ocean, year to date through September, °C against the 1901–2000 average. Recomputing the averages from NOAA’s monthly values reproduces each figure.²

Caveat. The records are narrow. Each of the four record months beat 2023 by less than a tenth of a degree, small enough that later revisions to provisional data could narrow it, and Copernicus has noted that not every dataset ranks these months first. What is robust is the direction: in NOAA’s record the ocean has run at or above its 2023 peak for a third of a year.

What we don't know

How much of the 2026 rise is El Niño and how much is the underlying warming trend is not something these monthly figures can separate; NOAA says El Niño contributed significantly but does not quantify it. Recent months are provisional. Rankings depend on the dataset — NOAA, Copernicus, NASA and the UK Met Office use different methods and can differ on close calls. Whether 2026 ends as the second-warmest year depends on October to December.

Method. Temperatures are NOAA NCEI global surface temperature anomalies (NOAAGlobalTemp) against the 1901–2000 average, taken from NOAA’s Climate at a Glance time series retrieved on 10 October 2026, a vintage that includes September 2026 and matches NOAA’s September report. A “record month” means the highest anomaly for that calendar month in NOAA’s 1850–2026 record; the margins over 2023 (0.03–0.08°C) and the year-to-date means were recomputed in code from the monthly values and match NOAA’s published figures. The outlook for 2026 is NOAA’s probabilistic assessment and is kept out of the headline and hero figures.

Sources. Numbered, highest tier first; each inline citation points here.

T1NOAA National Centers for Environmental Information, Monitoring Global Temperature and Precipitation in September 2026, 9 October 2026. Retrieved 10 Oct 2026.
T1NOAA NCEI, Climate at a Glance: global time series (global ocean and global land-and-ocean, monthly, September-only and year-to-date series). Retrieved 10 Oct 2026.
T1Copernicus Climate Change Service (ECMWF), August was world’s joint-hottest month on record, 10 September 2026. Retrieved 10 Oct 2026.

Corrections. None. Material corrections will be logged here with date.

Figures to 10 Oct 2026. Noodle News · v1.0 · ocean-temperature-four-record-months.