Objective To understand the seasonal characteristics of hand, foot and mouth disease (HFMD) in Xining of Qinghai province from 2013 to 2022, and provide evidence for the prevention, control, and early warning of HFMD.

Methods The monthly case information of HFMD in Xining from 2013 to 2022 were collected from the China Disease Prevention and Control Information System for a systematically analysis with seasonal index, concentration method, and circular distribution method.

Results A total of 10 228 HFMD cases were reported in Xining from 2013 to 2022, with an average annual incidence rate of 43.50/100 000. The annual concentration of HFMD from 2013 to 2022 was 0.57, indicating a strong seasonality. The analysis results of the seasonal index method showed that the incidence of HFMD was high during May-August. The circular analysis results showed that r was 0.62 and \bar \alpha was 187.38°(Z=3 976.224＞Z_0.05, P＜0.001), the incidence peak of HFMD was on 8^th July, and the high incidence period was from 13^th May to 3^rd September. There was a high correlation between the M value by the concentration method and the r value by the circular distribution method with a Pearson coefficient of 1.000 (P<0.001).

Conclusion The incidence of HFMD had strong seasonal characteristics in Xining from 2013 to 2022, with the high incidence between May and August each year. It is necessary to take appropriate prevention and control measures before the high incidence period of HFMD to effectively reduce the incidence and spread of HFMD.