Seasonal climate summary for the southern hemisphere (summer 2019–20): a summer of extremes

Abstract

This is a summary of the southern hemisphere atmospheric circulation patterns and meteorological indices for summer 2019–20; an account of seasonal rainfall and temperature for the Australian region is also provided. The antecedent climate conditions and climatic drivers for summer 2019–20 resulted in unprecedented extremes for Australia, with many heat and fire weather extremes. The austral summer of 2019–20 was staged to be hot and dry, with climate drivers supporting higher than average temperatures and lower than average rainfall. These conditions contributed to the highest recorded monthly accumulated national Forest Fire Danger Index. As the dominant climate influence for December receded during the season, dynamic (weather) processes dominated for changeable conditions – particularly in the mid-latitudes. Both January and February were among the 10 hottest on record, although several mid-latitude sites experienced unusually cool days. Across the rest of the hemisphere, conditions were also extreme, with notable drought conditions persisting from spring over large parts of South America. Temperature anomalies for land and ocean areas of the southern hemisphere were respectively the third and second highest on record.