2019 has been another very warm year and is likely to be in the three warmest years on record globally.  This means that the last six years have been the six warmest, with decadal mean temperatures now near 1 °C above pre-industrial levels, as concentrations of major greenhouse gases such as CO2 and methane reach their highest levels in the instrumental record. Arctic and Antarctic sea-ice extent was well below average throughout the year, and summer surface melting on Greenland was above average, although less extreme than in 2012 (the historical record holder).

Two exceptional heatwaves affected western and northern Europe in summer 2019, with national records set, some by margins greater than 2 °C, in countries including France, Germany, Belgium, the Netherlands and the United Kingdom. 1,500 deaths in France were attributed to the extreme heat. Other areas to experience exceptional summer heat included Siberia, Alaska, central Asia and much of Australia. In addition to eastern Australia, other parts of the world to experience significant drought included the Horn of Africa, the Mekong basin in south-east Asia, south-east India, and central Chile. Whilst the northern summer of 2019 did not have wildfires as destructive as those of 2018, fire activity was exceptionally high in Alaska and Siberia, while above-normal fire activity also affected the Amazon basin.

Whilst overall tropical cyclone activity globally was not exceptionally high, there were a number of very destructive storms. Idai, which hit Mozambique in March, caused the heaviest casualties known for a southern hemisphere cyclone in at least the last century, whilst Dorian caused catastrophic damage and heavy casualties in the Bahamas. Flooding was mostly less acute than in 2018, with near-average monsoon seasons in the Indian subcontinent and the African Sahel, although long-lived floods affected the Mississippi basin in the United States.