ORIGINAL PAPER Variation of October to December rainfall in Tanzania and its association with sea surface temperature Golden Melkiory Kavishe 1,2 & Paul Tilwebwa Shelleph Limbu 1,3 Received: 12 June 2019 /Accepted: 3 June 2020 # Saudi Society for Geosciences 2020 Abstract Rainfall variability during short rains from October to December (OND) leaves the country vulnerable to floods and droughts. This study used statistical analysis methods (Empirical Orthogonal Function EOF, Singular Value Decomposition SVD, Composite and Correlation analysis) to investigate the variability of OND rainfall and its association to Sea Surface Temperature (SST) and how the extreme weather events have been influenced by SSTs. The study showed that the Indian Ocean Dipole (IOD) events have a wider and stronger impact on OND rainfall variability over Tanzania than the El Niño Southern Oscillation (ENSO) events with a significant correlation coefficient value of r = 0.77 against r = 0.48, respectively. Analysis revealed that the year of 2015 received less rainfall than that of 1997 even though it had stronger Niño 3.4 signal than that of 1997 due to neutral state conditions of IOD events in 2015 which is associated by weak easterly winds advecting moist air towards the region. The study shows that the area received above average rainfall when El Niño and positive phase of IOD events occurred simultaneously like that of 1997. The rainfall pattern varies to large extent due to SST variability over the western and eastern Indian Ocean. The variability of SST anomalies observed over the western and southeastern Indian Ocean captured the IOD pattern in the first and second SVD mode. Findings of this study will improve our understanding of the occurrence of extreme events, monitoring and issuing early warning of extreme weather events. Keywords Tanzania . OND rainfall . Sea surface temperature . El Niño southern oscillation . Indian Ocean dipole Introduction Recent rainfall outlook for the Greater Horn of Africa (GHA) published by World Meteorological Organization on February 2017, suggested that drought is set to worsen in GHA coun- tries after the two consecutive poor rainfall seasons in 2016. Tanzania is among the GHA most vulnerable region/country to weather-related risks, such as droughts and floods (Mutai and Ward 2000; ICPAC 2017). Although Tanzania’s rainfall is much linked to global meteorological phenomena such as El Niño Southern Oscillation (ENSO) as studied by Kijazi and Reason (2005); Mahongo and Francis (2013), it is still not clear how the magnitude of ENSO influences the amount of rainfall during OND season. It is well known that in 1997 Tanzania received countrywide heavy rainfall caused by the famous ENSO event in 1997/98. In recent years, for instance in 2015, Tanzania did not receive- enough rainfall amount, although it was predicted to be heavy based on the observed high positive ENSO indices on the Pacific Ocean which were higher than the ENSO indices observed in 1997. In 2016 many parts of the country received below average rainfall which triggered many negative impacts in many sectors. The variation of rainfall amount received in relationship to ENSO strength stresses an important issue of this study to assess the relationship of ENSO strength and the amount of rainfall re- ceived over Tanzania in association to circulation anomalies. Tanzania relies mainly on the rain fed type of agriculture which employs majority of the labour force. This makes the country highly vulnerable to adverse impacts of rainfall vari- ability. Agriculture sector is an unequivocal main source of Responsible Editor: Zhihua Zhang * Paul Tilwebwa Shelleph Limbu paul.limbu@ymail.com 1 College of Atmospheric Sciences, Nanjing University of Information Science and Technology, 219 Ningliu Road, Nanjing, Jiangsu Province, People’s Republic of China 210044 2 Tanzania Meteorological Authority, P. O. Box, 3056 Dar es Salaam, Tanzania 3 Physics Department, University of Dar es Salaam, P. O. Box, 35063 Dar es Salaam, Tanzania https://doi.org/10.1007/s12517-020-05535-z / Published online: 23 June 2020 Arabian Journal of Geosciences (2020) 13: 534