Physical Science International Journal

This study quantifies the statistical relationships among four meteorological variables: sunshine duration, rainfall amount, rainfall rate, and relative humidity using six years of monthly observational data (2015–2020, n = 72) sourced from the Nigerian Meteorological Agency (NiMet). The statistical analyses included a one-way analysis of variance (ANOVA) F-test, Pearson Correlation Coefficient (PCC) analysis, and linear regression trend modelling. The results show that the annual mean sunshine duration is 10.235 hr/day (3,740 hr/yr), corresponding to an estimated Global Horizontal Irradiance (GHI) of 2,431 kWh/m²/yr, indicating that Sokoto State has a favourable solar resource. One-way ANOVA confirms that the monthly means of all four variables differ significantly, indicating a strong seasonal structure in the dataset. All annual ANOVA results are non-significant (p > 0.05). PCC analysis reveals significant negative correlations between sunshine duration and rainfall (r = − 0.7179, p < 0.001), and between sunshine duration and relative humidity (r = − 0.6342, p < 0.001), confirming that moisture parameters serve as reliable inverse proxies of solar resource availability in Sokoto’s Sahel climate. Rainfall and rain rate are nearly collinear (r = 0.9515, p < 0.001), while rainfall and relative humidity share a strong positive association (r = 0.8209, p < 0.001), together forming a physically coherent wet-season moisture cluster. The annual mean rainfall is low, at 24.45 mm/yr, concentrated almost entirely in the June–September window. Year-on-year trends indicate a downward tendency for sunshine (Overall Trend) and rainfall, while rain rate and relative humidity exhibit slight upward tendencies, although none of the annual ANOVA results are statistically significant. A model excluding sunshine was developed; it explains 52% of the monthly variance and achieves a MAPE of 5.1% on the data.