The time-varying characteristics of cable modal parameters and cable tensions under good weather and heavy rain are systematically analyzed based on the one-year acceleration and temperature monitoring data of five cables on a long-span cable-stayed bridge. The modal frequency and damping ratio are derived using the fast Fourier transform（FFT）and stochastic random identification（SSI）method. It is found that the cable vibrates greatly under wind and rain conditions. The low-order mode dominates the vibration，and the modal damping ratio has certain differences in the two circumstances. The tension force of each cable throughout the year，derived using the frequency method，is a non-stationary time series and has annual and daily periodic fluctuations. The correlation analysis of the cable tension and temperature shows that the correlation between the two of each cable is different， even differs on the same cable in different temperature ranges. The half-power bandwidth method is used to calculate the damping ratio of each cable for one year，the autocorrelation function and its self-power spectrum are obtained， and the edge probability density distribution function of the damping ratio is also obtained by fitting. The analysis shows that the damping ratio of each cable has the periodic components of 1 day，12 hours，and 6 hours，and its edge probability density function can be described by Burr distribution. The damping ratio of the cable is less affected by the ambient temperature but more by the vehicle load.