What Happened
- According to the Copernicus Climate Change Service (C3S), January 2026 was the fifth-warmest January on record globally, with an average surface air temperature of 12.95°C — 0.51°C above the 1991–2020 reference average.
- January 2026 was 1.47°C above the estimated 1850–1900 pre-industrial average, just below the 1.5°C Paris Agreement threshold, measured using the ERA5 reanalysis dataset.
- Despite the global warmth, severe cold conditions gripped large parts of North America, Europe, and Siberia during the second half of January, driven by a wavier-than-usual polar jet stream that allowed Arctic air to spill southward into mid-latitudes.
- January 2026 was 0.28°C cooler than January 2025, which holds the record for warmest January on record.
- The data illustrates the paradox of global warming: even as the planet's average temperature rises, regional cold extremes can intensify due to disruptions in atmospheric circulation patterns.
Static Topic Bridges
Copernicus Climate Change Service (C3S) and ERA5
The Copernicus Climate Change Service is part of the EU's Copernicus Earth Observation Programme, operated by the European Centre for Medium-Range Weather Forecasts (ECMWF). It provides free, open access to authoritative climate data and analyses. The ERA5 reanalysis dataset — the fifth generation ECMWF atmospheric reanalysis — covers global climate data from January 1940 to the present, combining model data with observations to produce a comprehensive record of the global atmosphere.
- ERA5 spatial resolution: ~31 km globally; temporal resolution: hourly
- Data coverage: 1940 to present (continuously updated)
- Used for: Monthly global temperature monitoring, tracking climate anomalies, IPCC reports
- Pre-industrial baseline used: 1850–1900 average (standard scientific benchmark)
- C3S publishes monthly Climate Bulletins — primary source for global temperature rankings
Connection to this news: The January 2026 ranking as fifth-warmest was determined using ERA5 data, making it the authoritative reference for UPSC questions on global temperature monitoring agencies and datasets.
The Polar Vortex and Jet Stream Disruption
The polar vortex is a large area of low pressure and cold air surrounding Earth's poles. The polar jet stream — a fast-moving band of westerly winds in the upper troposphere — normally acts as a barrier containing Arctic air. When the jet stream weakens or becomes wavier (due to Arctic warming reducing the temperature gradient between the Arctic and mid-latitudes), cold Arctic air can "spill" southward, causing extreme cold events in mid-latitude regions like North America and Europe.
- Arctic amplification: The Arctic is warming 2–4 times faster than the global average (a well-documented phenomenon)
- Jet stream waviness (Rossby waves): Increases as the temperature differential between Arctic and equator narrows
- Sudden Stratospheric Warming (SSW): Can disrupt the polar vortex and trigger cold air outbreaks in Europe and North America
- The phenomenon explains why a globally warm January can coincide with record-breaking cold in specific regions
Connection to this news: The record cold in Europe during January 2026 despite global warmth is explained by polar jet stream disruption — a direct consequence of Arctic amplification driven by climate change.
Global Temperature Records and the Pre-Industrial Baseline
Scientific monitoring of global temperatures uses a pre-industrial baseline of 1850–1900 to measure anomalies — the amount by which temperatures deviate from this reference period. Multiple agencies independently monitor global temperatures: Copernicus/ERA5 (EU), NASA GISS (USA), NOAA (USA), UK Met Office/HadCRUT (UK), and Berkeley Earth. The year 2024 crossed 1.5°C above the pre-industrial average as an annual mean for the first time, though this was a single-year breach, not the long-term sustained warming the Paris Agreement refers to.
- Hottest year on record: 2024 (~1.47°C above pre-industrial)
- Hottest January on record: January 2025
- January 2026: Fifth warmest January; 1.47°C above pre-industrial
- 17 of the last 18 months (up to early 2025) were the warmest on record for their respective months
- The Paris Agreement's 1.5°C limit refers to long-term (multi-decadal) averages, not single-year or single-month readings
Connection to this news: January 2026's 1.47°C anomaly — just 0.03°C below the Paris threshold — in a context where the trend is clearly upward, makes every monthly report relevant for tracking proximity to the agreement's limits.
World Meteorological Organization (WMO) and Climate Monitoring
The WMO, a specialised agency of the United Nations, coordinates global meteorological, climatological, and hydrological services across 193 member states. It publishes the annual State of the Global Climate report, which is a key reference for UPSC questions on climate organisations. The WMO confirms global temperature records and coordinates the Global Climate Observing System (GCOS).
- WMO established: 1950 (successor to the International Meteorological Organization, 1873)
- Headquarters: Geneva, Switzerland
- Global Climate Observing System (GCOS): Network of satellites, weather stations, ocean buoys that feed data into ERA5 and other datasets
- WMO State of Climate 2024: Confirmed 2024 as hottest year on record, with global mean temperature 1.55°C above pre-industrial
- India's nodal agency for WMO: India Meteorological Department (IMD), under Ministry of Earth Sciences
Connection to this news: WMO corroborated the Copernicus findings about January 2026 temperatures and the broader pattern of extreme weather events marking the start of 2026.
Key Facts & Data
- January 2026 average global surface temperature: 12.95°C
- Anomaly vs 1991–2020 average: +0.51°C
- Anomaly vs pre-industrial (1850–1900): +1.47°C
- Ranking: Fifth warmest January on record
- Comparison: 0.28°C cooler than January 2025 (warmest January on record)
- Cold wave driver: Wavier polar jet stream allowing Arctic air incursion into Europe/North America/Siberia
- Copernicus/ERA5: EU's ECMWF-operated reanalysis dataset, coverage 1940–present, ~31 km resolution
- Paris Agreement threshold: 1.5°C above pre-industrial (long-term sustained, not single-month)
- WMO State of Climate 2024: Confirmed 2024 global mean at 1.55°C above pre-industrial