Abstract: Under conditions of growing climate instability and the simultaneous ageing of urban water infrastructure, the question of how precipitation is distributed across seasons is no longer a purely descriptive climatological issue but a practical planning problem. Cities located in sharply continental climate zones are especially exposed to this challenge: precipitation is uneven within the year, interannual fluctuations are substantial, and short periods of excess rainfall may alternate with extended dry intervals. In such settings, engineering water systems operate under structurally variable loads, which increases both operational uncertainty and long-term investment risk. This study examines the seasonal and interannual behavior of monthly precipitation in the city of Kostanay and develops a forecast framework based on a Seasonal autoregressive integrated moving average specification. The empirical analysis relies on long-term hydrometeorological observations, which make it possible to distinguish persistent seasonal regularities from irregular stochastic deviations and extreme monthly anomalies. Particular attention is given to how these variations translate into uneven stress on drainage and water-management systems rather than being treated as abstract statistical noise. Model identification and parameter selection were conducted step-by-step, with separate evaluation of seasonal structure, autocorrelation patterns, and forecast error behavior. Validation results demonstrate a high level of agreement between observed and estimated values across different years, including periods with atypical precipitation distribution. This indicates that seasonal stochastic time-series models of this class can serve as a reliable analytical instrument for short- and medium-term precipitation forecasting at the city level. From a practical standpoint, the results support the inclusion of model-based seasonal precipitation forecasts in urban water-infrastructure planning, climate risk assessment, and adaptation policy design. The proposed approach is intended not as a purely theoretical exercise but as a decision-support tool for municipal and sectoral planning under conditions of climatic uncertainty.

Keywords: water resources, precipitation variability, seasonal patterns, urban infrastructure, urban water management, climate risk

Pages: 712-735