All consecutive suicide attempters admitted to health care in Helsinki from January 1997-January 1998 were studied. Overall, the rate of suicide attempts varied markedly during the study period, peaking in autumn & being lowest during winter. Substance use disorders best explained suicide attempts occurring on weekends. There was considerable temporal variation among patients with mood disorders compared to only slight variation among patients with schizophrenia spectrum disorders. Subjects tended to contact health services in the late evening & around midnight. Those contacting health services outside normal hours received psychiatric consultation less frequently than others & were referred to aftercare less often. (27 refs.) JA