Climate-Related Associations and Seasonal Variability of Municipal Waste Fractions: A County-Level Case Study from Romania

The aim of this study was to evaluate the s seasonal variability and climate-related associations of the main municipal waste fractions collected within the municipal waste management system of Bacau County, Romania, during the 2019–2024 period. The analysis integrated monthly municipal waste data with climatic variables obtained from the NASA POWER database, including air temperature, precipitation, wind speed, and solar radiation. Seasonal variability was investigated using one-way analysis of variance (One-way ANOVA), Tukey’s HSD post hoc test, and seasonal index analysis, while climate–waste relationships were assessed using Pearson correlation analysis and the cross-correlation function (CCF). The results revealed significant seasonal differences in residual waste and biowaste, whereas recyclable fractions (plastic, paper and cardboard, and glass) showed no statistically significant seasonal variation. Residual waste exhibited the strongest relationships with climatic factors, being positively correlated with air temperature (r = 0.794) and solar radiation (r = 0.649), and negatively correlated with wind speed (r = −0.670). Biowaste showed weak contemporaneous associations, while exploratory cross-correlation analysis did not provide robust evidence of delayed climatic effects. The study demonstrates that the relationships between climatic conditions and collected waste quantities are fraction-specific and cannot be adequately characterized by analyzing total municipal waste quantities alone. The proposed analytical framework can support the development of forecasting tools and adaptive planning strategies for municipal waste management in the context of climate change.