Abstract / Summary
Influenza is a major global public health issue, and meteorological factors significantly influence its seasonal patterns. Nanchang is located in a subtropical monsoon climate zone, yet there is currently a lack of systematic research on the epidemiological characteristics of influenza and its association with meteorological factors. This study aims to describe the spatiotemporal patterns of influenza prevalence in Nanchang, analyze the characteristics of diagnostic delays, and quantitatively assess the association between meteorological factors and influenza incidence. This study included confirmed influenza cases in Nanchang from January 2023 to March 2026 ( n = 120,308) and 10 meteorological indicators from the same period, which were aggregated and analyzed on a weekly basis. Statistical analyses were conducted using Seasonal-Trend decomposition using Loess, Spearman’s correlation, Random Forest regression, and the Distributed Lag Nonlinear Model. In Nanchang, influenza is most prevalent during the winter and spring, with the highest incidence rate recorded in 2025 (837.36 per 100,000), and the peak of the outbreak occurring in Week 49 of 2025. Individuals aged 0–19 accounted for 76% of cases, with students constituting the largest group. Among the various districts and counties, Xihu District and Honggutan District bore the heaviest disease burden. 89.64% of cases were diagnosed within 2 days of symptom onset, while the proportion of delayed diagnoses was significantly higher among people aged 60 and older and among farmers. The random forest model indicated that average temperature had the highest variable importance, exhibiting a U-shaped relationship, followed by wind speed, cloud cover, and precipitation. Quantitative analysis using a distribution-lag nonlinear model showed that low wind speed was the strongest associated factor (cumulative RR = 6.26 at 1.43 m/s), while low temperatures showed a cumulative RR of 2.88 and high temperatures showed a cumulative RR of 0.03. Low wind speeds, temperature, and precipitation were significantly associated with influenza activity in Nanchang. It is recommended that meteorological indicators may provide supportive information for influenza surveillance and early warning. Children and adolescents are the priority groups for prevention and control, while early diagnosis capabilities for people aged 60 and older and rural populations need to be improved. Not applicable.