Objective To identify seasonal and temporal variations in daily incidence of homicides and suicides in Cali and Manizales, Colombia during 2008–2015.Materials and methods An ecological time series study was performed using negative binomial regression models for daily incidence of homicides and suicides; analyses were controlled for yearly trends and temporal autocorrelations.Results Saturdays, Sundays, December holidays as well as New Year and New Year's Eve were associated with an increased risk of homicides in both cities. Suicide risk increased during December holidays and New Year in both cities. In addition, the suicide risk increased on paydays, Saturdays, Sundays, and Mondays in Cali, and it decreased during the Holy Week holidays in Manizales. December patterns of suicides and homicides are the opposite in each city, and between cities.Conclusions The incidences of homicides and suicides are not homogeneous over time. These patterns can be explained partially by alcohol consumption and changes in people's routine activities which may modify exposure to violent circumstances.