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Inter-Annual Variability of Rainfall, Temperature and Agroclimatic Indices in Kaduna State, Nigeria (2010-2025)
Subject area: Science,Engineering and Technology · Area of research: Environmental Science
Abstract
This study examined the inter-annual variability of rainfall, temperature and agroclimatic indices in Kaduna State, Nigeria, over sixteen years, 2010 to 2025. Daily rainfall and temperature records from the Nigerian Meteorological Agency were aggregated into monthly and annual values and analysed for variability in rainfall onset, cessation, length of the growing season, and early and late season dry spells, using Instat, Microsoft Excel and Python. Mean maximum temperature rose gradually across the period, from 37.4 °C in 2012 to a peak of 38.6 °C in 2025, representing an average annual increase of approximately 0.039 °C. Annual rainfall fluctuated between 1,151.8 mm and 2,156.6 mm, with a mean of 1,561.3 mm and a coefficient of variation of approximately 18%, reflecting a regression slope of 12.17 mm per year that was not statistically significant (p = 0.230). Rainfall onset ranged from 4 May to 1 June, with a statistically significant delay of 1.057 days per year (p = 0.030), amounting to a cumulative delay of about 16 days over the study period. Cessation dates ranged from day 285 to day 318 of the year, with a weak, non-significant trend toward earlier cessation, while the length of the growing season declined gradually from a maximum of 194 days in 2018 to a minimum of 150 days in 2023. Early season dry spells showed only a marginal increase, whereas late season dry spells rose markedly, by approximately 0.874 days per year, corresponding to a cumulative increase of about 14 days, signalling intensifying moisture stress during the reproductive and grain filling stages of major crops. The findings demonstrate that the principal climatic challenge confronting Kaduna State is not a change in total rainfall volume but increasing intra-seasonal variability, delayed onset, a shortening growing season and intensifying late season dry spells. The study recommends strengthened seasonal forecasting, the promotion of early and medium maturing crop varieties, soil moisture conservation practices and climate informed agricultural advisory services to support adaptation in the Guinea savanna zone of Nigeria.
Keywords
climate variability; rainfall; temperature; growing season; dry spells; Kaduna State
How to cite this paper
@article{1724235,
author = {Aganbi Blessing, J. I. Magaji, M. Alkali, Olatunji Labake Rebecca},
title = {Inter-Annual Variability of Rainfall, Temperature and Agroclimatic Indices in Kaduna State, Nigeria (2010-2025)},
journal = {Iconic Research And Engineering Journals},
year = {2026},
volume = {10},
number = {4},
pages = {3367-3376},
issn = {2456-8880},
url = {https://www.irejournals.com/formatedpaper/1724235.pdf},
abstract = {This study examined the inter-annual variability of rainfall, temperature and agroclimatic indices in Kaduna State, Nigeria, over sixteen years, 2010 to 2025. Daily rainfall and temperature records from the Nigerian Meteorological Agency were aggregated into monthly and annual values and analysed for variability in rainfall onset, cessation, length of the growing season, and early and late season dry spells, using Instat, Microsoft Excel and Python. Mean maximum temperature rose gradually across the period, from 37.4 °C in 2012 to a peak of 38.6 °C in 2025, representing an average annual increase of approximately 0.039 °C. Annual rainfall fluctuated between 1,151.8 mm and 2,156.6 mm, with a mean of 1,561.3 mm and a coefficient of variation of approximately 18%, reflecting a regression slope of 12.17 mm per year that was not statistically significant (p = 0.230). Rainfall onset ranged from 4 May to 1 June, with a statistically significant delay of 1.057 days per year (p = 0.030), amounting to a cumulative delay of about 16 days over the study period. Cessation dates ranged from day 285 to day 318 of the year, with a weak, non-significant trend toward earlier cessation, while the length of the growing season declined gradually from a maximum of 194 days in 2018 to a minimum of 150 days in 2023. Early season dry spells showed only a marginal increase, whereas late season dry spells rose markedly, by approximately 0.874 days per year, corresponding to a cumulative increase of about 14 days, signalling intensifying moisture stress during the reproductive and grain filling stages of major crops. The findings demonstrate that the principal climatic challenge confronting Kaduna State is not a change in total rainfall volume but increasing intra-seasonal variability, delayed onset, a shortening growing season and intensifying late season dry spells. The study recommends strengthened seasonal forecasting, the promotion of early and medium maturing crop varieties, soil moisture conservation practices and climate informed agricultural advisory services to support adaptation in the Guinea savanna zone of Nigeria.},
keywords = {climate variability; rainfall; temperature; growing season; dry spells; Kaduna State},
month = {October},
}