CSIRO PUBLISHING Journal of Southern Hemisphere Earth Systems Science, 2020, 70, 353–372 Seasonal Climate Summary https://doi.org/10.1071/ES19038 Seasonal climate summary for the southern hemisphere (winter 2018): fifteenth-warmest and fourteenth-driest Zhi-Weng Chua Bureau of Meteorology, GPO Box 1289, Melbourne, Vic. 3001, Australia. Email:
[email protected] Abstract. This is a summary of the southern hemisphere atmospheric circulation patterns and meteorological indices for winter 2018; an account of seasonal rainfall and temperature for the Australian region and the broader southern hemisphere is also provided. The climate influences from the El Nin˜o–Southern Oscillation and the Indian Ocean Dipole were weak, with both demonstrating neutral conditions over the season. It was a dry and warm winter for Australia, being the fourteenth-driest and fifteenth-warmest (in terms of mean temperature) in a record of 119 and 109 years respectively. The warm and dry conditions were particularly pronounced over eastern Australia during July. Maximum temperatures were above average while minimum temperatures were below average. Keywords: Australian climate, ENSO, IOD, seasonal climate summary, seasonal rainfall, seasonal temperature, southern hemisphere climate, southern hemisphere winter, winter climate. Received 22 April 2020, accepted 7 May 2020, published online 17 September 2020 1 Introduction 2016. Values were largely neutral for the rest of the period, with This summary reviews the southern hemisphere and equatorial the brief presence of weak La-Nin˜a-like values from late 2017 to climate patterns for winter 2018, with particular attention given early 2018. Over the winter of 2018, the SOI values were –5.5, to the Australasian and equatorial regions of the Pacific and 1.6 and –6.9 in June, July and August respectively, producing a Indian ocean basins (Fig.