This study analyzed the long-term trend and variability of climatic parameters and their effects on maize (Zea mays L.) production in Ejule, Ofu Local Government Area, Kogi State, Nigeria, over a thirty-one-year period (1992–2023). Climatic data including rainfall, temperature, soil temperature, relative humidity, solar radiation, and wind speed were obtained from the Nigerian Meteorological Agency (NIMET), Lokoja station, while maize yield data were sourced from the Kogi State Agricultural Development Project (KADP) and cross-validated with records from the Federal Ministry of Agriculture and Rural Development (FMARD). Descriptive statistics, trend analysis, and regression models were employed to examine long-term climatic shifts, yield responses, and their interactions. The results revealed strong inter-annual rainfall variability without a consistent long-term trend, while temperature exhibited a significant warming trajectory of 0.3–0.4°C per decade, closely mirrored by rising soil temperatures. Maize yields stagnated during the 1990s and early 2000s, improved moderately in the 2010s, peaked at 2.49 t/ha in 2019, and later stabilized at 2.13–2.17 t/ha between 2021 and 2023. Regression analysis showed that rainfall exerted a modest but significant positive influence on yield (β = 0.192, R² = 0.17, p < 0.05), whereas temperature (β = –0.355, R² = 0.31, p < 0.01) and soil temperature (β = –0.312, R² = 0.25, p < 0.05) exerted significant negative effects, confirming that maize production in Ejule is more constrained by thermal stress than by rainfall variability. The study concludes that climate variability particularly rising temperatures poses a critical threat to food security in the Guinea Savanna. Without targeted interventions, maize yields are likely to remain suppressed despite occasional favorable rainfall years. It recommends the adoption of climate-smart agricultural practices, including the use of heat- and drought-tolerant maize varieties, improved soil and water management, small-scale irrigation, and strengthened climate information services, as essential pathways for safeguarding household food security and building resilience in the region.