We investigated suicide timing over different time periods by age, sex and race/ethnicity. A total of 122,107 suicide deaths were identified from the population-based U.S. National Violent Death Reporting System in 18 U.S. states from 2003 through 2014. Suicides significantly increased (p < .05) from March to peak in September before falling, the first week of the month, and early in the week. Suicides also significantly increased (p < .05) in the morning, mainly peaking during the afternoon, although suicides in adolescents peaked in the evening and in those 65-years and older peaked in the morning. Comprehensive prevention efforts should focus on those at overall increased suicide risk and at peaks of high suicide frequency, especially among those vulnerable subgroups.