Rainfall timing: variation, characteristics, coherence, and interrelationships in Nigeria

  • Omon A. Obarein
  • Amobichukwu C. AmanambuEmail author
Original Paper


This study sought to improve general understanding on rainfall timing in Nigeria. Observed monthly rainfall data for 38 meteorological stations, spanning 30 years was utilized, and the dates of onset and cessation of rainfall were estimated using Walter’s method. The interrelationships among the variables and the dependency of the amount of rainfall were calculated using Pearson’s moment correlation coefficient and multiple regression, respectively. The variance of the Standardized Anomaly Index (SAI) was used as a measure of spatial coherence. The study revealed divergent characteristics between the onset and the cessation of rainfall; progressing in opposite direction, with a very high latitudinal variation in each. Rainfall onset has a relatively high interannual variability, with an average CV of 21%, compared to 3.9% for cessation. Onset also has a larger spatial range of 137 days, compared to 82 days for cessation. Additionally, rainfall cessation was found to be more spatially coherent than the onset, but both revealed a weak spatial coherence. The relative spatial incoherence and high interannual variability of onset contrive to make it much less predictable than cessation. Interestingly, rainfall amount shows greater association with, and dependency on, onset, cessation, and rainy season length in stations of the extreme north, than in southern stations.



We would like to thank Professor J. O. Ayoade for his insight and comments that improved the paper. We are grateful to the reviewers for their intelligent input. We would also like to thank the Nigerian Meteorological Agency (NIMET) for the provision of the data used to complete this project.


  1. Adefisan EA, Abatan AA (2015) Agroclimatic zoning of Nigeria based on rainfall characteristics and index of drought proneness. J Environ Earth Sci 5:115–127Google Scholar
  2. Adelekan IO, Adegebo BO (2014) Variation in onset and cessation of the rainy season in Ibadan. J Sci Res 13:13–21Google Scholar
  3. Amanambu AC, Li L, Egbinola CN, Obarein OA, Mupenzi C, Chen D (2019) Spatio-temporal variation in rainfall-runoff erosivity due to climate change in the lower Niger Basin, West Africa. CATENA 172:324–334CrossRefGoogle Scholar
  4. Amekudzi LK, Yamba EI, Preko K, Asare EO, Aryee J, Baidu M, Codjoe SN (2015) Variabilities in rainfall onset, cessation and length of rainy season for the various agro-ecological zones of Ghana. Climate 3(2):416–434Google Scholar
  5. Ati OF, Stigter CJ, Oladipo EO (2002) A comparison of the methods to determine the onset of the growing season in northern Nigeria. Int J Climatol 22:731–742CrossRefGoogle Scholar
  6. Ayoade JO (2004) Introduction to climatology for the tropics, 2nd edn. In: Spectrum BooksGoogle Scholar
  7. Ayoade JO (2008) Techniques in climatology. Stirling-Horden Publishers LtdGoogle Scholar
  8. Bello NJ (1996) An investigation of the characteristics of the onset and cessation of the rains in Nigeria. Theor Appl Climatol 54:161–173CrossRefGoogle Scholar
  9. Bello NJ (1997) Investigating the spatial pattern of the characteristics of the onset and cessation of the rains in Nigeria. GeoJournal 43:113–123CrossRefGoogle Scholar
  10. Benoit P (1977) The start of the growing season in northern Nigeria. Agric Meteorol 18:91–99CrossRefGoogle Scholar
  11. Camberlin P, Okoola RE (2003) The onset and cessation of the ‘long rains’ in eastern Africa and their inter-annual variability. Theor Appl Climatol 75:43–54Google Scholar
  12. Camberlin P, Moron V, Okoola R, Philippon N, Gitau W (2009) Components of the rainy seasons’ variability in Equatorial East Africa: onset, cessation, rainfall frequency and intensity. Theor Appl Climatol 98:237–249CrossRefGoogle Scholar
  13. Chen PY, Popovich PM (2002)Correlation: parametric and nonparametric measures. Sage publicationsGoogle Scholar
  14. Dunning CM, Black EC, Allan RP (2016) The onset and cessation of seasonal rainfall over Africa. J Geophys Res: Atmos 121(19):11,405–11,424Google Scholar
  15. Gebremichael A, Quraishi S, Mamo G (2014) Analysis of seasonal rainfall variability for agricultural water resource management in Southern Region, Ethiopia. J Nat Sci Res 4:56–80Google Scholar
  16. Glass GV, Hopkins KD (1996) Statistical methods in education and psychology, 3rd edn. Allyn& BaconGoogle Scholar
  17. Hachigonta S, Reason CJC, Tadross M (2008) An analysis of onset date and rainy season duration over Zambia. Theor Appl Climatol 91:229–243CrossRefGoogle Scholar
  18. Kanemasu ET, Stewart JI, van Donk SJ, Virmani SM (1990) Agroclimatic approaches for improving agricultural productivity in semi-arid tropics. Adv Soil Sci 13:273–309CrossRefGoogle Scholar
  19. Katz RW, Glantz MH (1986) Anatomy of a rainfall index. Mon Weather Rev 114:764–771CrossRefGoogle Scholar
  20. Kowal JM, Knabe DT (1972) An agroclimatological atlas of the Northern States of Nigeria. Ahmadu Bello University Press, Zaria, p 111Google Scholar
  21. Laux P, Kunstmann H, Bardossy A (2008) Predicting the regional onset of the rainy season in West Africa. Int J Climatol 28:329–342CrossRefGoogle Scholar
  22. Marteau R, Moron V, Philippon N (2009) Spatial coherence of monsoon onset over western and Central Sahel (1950–2000). J Clim 22:1313–1324CrossRefGoogle Scholar
  23. Moron V, Robertson AW, Ward MN (2006) Seasonal predictability and spatial coherence of rainfall characteristics in the tropical setting of Senegal. Mon Weather Rev 134:3248–3262CrossRefGoogle Scholar
  24. Moron V, Robertson AW, Ward MN, Camberlin P (2007) Spatial coherence of tropical rainfall at the regional scale. J Clim 20:5244–5263CrossRefGoogle Scholar
  25. Moron V, Robertson AW, Boer R (2009) Spatial coherence and seasonal predictability of monsoon onset over Indonesia. J Clim 22:840–850CrossRefGoogle Scholar
  26. Mubvuma MT (2013) Climate change: matching growing season length with maize crop varietal life cycles in semi-arid regions of Zimbabwe. Greener J Agric Sci 3:809–816Google Scholar
  27. Mugalavai EM, Kipkorir EC, Raes D, Rao MS (2008) Analysis of rainfall onset, cessation and length of the growing season for western Kenya. Agric For Meteorol 148:1123–1135CrossRefGoogle Scholar
  28. Mupangwa W, Walker S, Twomlow S (2011) Start, end and dry spells of the growing season in semi-arid southern Zimbabwe. J Arid Environ 75:1097–1104CrossRefGoogle Scholar
  29. Nayagam LR, Janardanan R, Mohan HS (2008) An empirical model for the seasonal prediction of southwest monsoon rainfall over Kerala, a meteorological subdivision of India. Int J Climatol 28:823–831CrossRefGoogle Scholar
  30. Nieuwolt S (1982) Tropical climatology: an introduction to the climates of the low latitudes. John Wiley & SonsGoogle Scholar
  31. Odekunle TO (2004) Rainfall and the length of the growing season in Nigeria. Int J Climatol 24:467–479CrossRefGoogle Scholar
  32. Odekunle TO (2006) Determining rainy season onset and retreat over Nigeria from precipitation amount and number of rainy days. Theor Appl Climatol 83:193–201CrossRefGoogle Scholar
  33. Odekunle TO, Adejuwon SA (2007) Assessing changes in the rainfall regime in Nigeria between 1961 & 2004. Geojournal 70:145–159CrossRefGoogle Scholar
  34. Oguntunde PG, Lischeid G, Abiodun BJ, Dietrich O (2014) Analysis of spatial and temporal patterns in onset, cessation and length of growing season in Nigeria. Agric For Meteorol 194:77–87CrossRefGoogle Scholar
  35. Oladipo EO, Kyari JD (1993) Fluctuations in the onset, termination and length of the growing season in Northern Nigeria. Theor Appl Climatol 47:241–250CrossRefGoogle Scholar
  36. Olaniran OJ (2002) Rainfall anomalies in Nigeria: the contemporary understanding. An Inaugural Lecture. Department of geography. University of IlorinGoogle Scholar
  37. Olaniran OJ, Sumner GN (1989) A study of climatic variability in Nigeria based on the onset, retreat, and length of the rainy season. Int J Climatol 9:253–269CrossRefGoogle Scholar
  38. Omotosho J, Balogun A, Ogunjobi K (2000) Predicting monthly and seasonal rainfall, onset and cessation of the rainy season in West Africa using only surface data. Int J Climatol 20:865–880CrossRefGoogle Scholar
  39. Recha CW, Makokha GL, Traore PS, Shinsanya C, Lodoun T, Sako A (2011) Determination of the seasonal rainfall variability, onset and cessation in semi-arid Tharaka district, Kenya. Theor Appl Climatol 108:479–494CrossRefGoogle Scholar
  40. Rutter J (2012) Variations in weather patterns on the ITCZ. Geofile online, No. 602. Nelson ThornesGoogle Scholar
  41. Sivakumar MVK (1988) Predicting rainy season potential from the onset of rains in Southern Sahelian and Sudanian climatic zones of West Africa. Agric For Meteorol 42:295–305CrossRefGoogle Scholar
  42. Smithson P, Addison K, Atkinson K (2008) The physical environment, 4th edn. RoutledgeGoogle Scholar
  43. Walter MW (1967) Length of the rainy season in Nigeria. Niger Geogr J 10:123–128Google Scholar

Copyright information

© Springer-Verlag GmbH Austria, ein Teil von Springer Nature 2019

Authors and Affiliations

  1. 1.Department of GeographyKent State UniversityKentUSA
  2. 2.Department of GeographyUniversity of FloridaGainesvilleUSA

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