Suicides in the general population are noted to occur more frequently than expected around death anniversaries, birthdays, and other calendar-specific dates, suggesting that emotionally significant dates may have important influences on the timing of suicide. We aimed to investigate the characteristics of psychiatric patients who die by suicide on a significant date, and to test whether three specific socio-demographic or clinical characteristics (age under 25 years; male gender; personality disorder diagnosis) are associated with the probability of a suicide death occurring on i) any significant date, ii) a patient’s birthday or iii) the death anniversary of a close contact. Using a representative whole population case series of suicides among psychiatric patients in the UK over the period 2011-2020, we analysed data on all patients who had died by suicide within in a year of being under the care of psychiatric services in the UK, to identify all those for whom the responsible clinician felt that the timing of death represented a significant date, and to specify these further. We found that 1,178/11,367 (10.4%) of all psychiatric patients who die by suicide are thought by the responsible clinician to have died on a significant date. Of these, 49.7% related to the patient’s birthday, 11% to the anniversary of a death of a close contact, 10.4% to another specific type of calendar-specific date (e.g. wedding anniversary, child’s birthday, New Year’s Eve), and 29% represented a mixture of event-specific dates and calendar-specific dates. We did not find evidence to support our hypothesis of an association between the three specific characteristics and suicide occurring around the time of a significant date, a patient’s birthday or a death anniversary. Contrary to this hypothesis, we found that male gender was negatively associated with suicide around a death anniversary (OR=0.69, 95% CI 0.49-0.98). We conclude that significant dates, particularly own birthday, may influence the timing of suicide among psychiatric patients and are likely to be important temporal risk factors for suicide.