La Niña Impacts on Southeastern African Climate: The Influence of Event Duration

ABSTRACT The multiyear La Niña event of 2020–2023, which brought with it several climate disasters across the globe, sparked both mainstream and scientific interest in La Niña events, which typically have received less attention than El Niño. In southern Africa, there is a general expectation in the scientific community and among user groups that La Niña events result in cool and wet summers. However, such impacts do not always occur and the full diversity of La Niña impacts, including multiyear events, has not been systematically explored. Here, various temperature and rainfall characteristics occurring during three categories of La Niña events—single, double, and triple year events are—investigated for the period 1970–2023. Space‐parameter bubble plots are used to display anomalies in mid‐late summer rainfall, heavy rain and dry spell frequencies, and in mean temperature and extreme heat days across four domains in southeastern Africa. Despite being relatively populated with important port cities and agriculture, not much work has focused on this region. Double‐year La Niña summers were the least consistent in exhibiting expected wet characteristics. During triple‐year events, the subtropical domains, southern Mozambique and eastern South Africa, showed the greatest tendency towards wet conditions, although a few seasons deviated significantly in rainfall distribution from their multiyear counterparts. In contrast, the tropical domains, southern Tanzania and northern Mozambique, more consistently were cooler than average than the subtropical domains. These findings highlight the diversity of La Niña impacts on summer conditions in southeastern Africa and show that La Niña events are not necessarily associated with cooler and wetter than average summers over the region.