The black carrion fly Hydrotaea rostrata Robineau-Desvoidy (Diptera: Muscidae) is a muscid, which occurs on approximately one-third of decomposing human corpses involved in homicide cases in south-western Australia. Work to date on its development rates is scant with only one published source available. The current study measured the precise developmental rates of this species using high repetition and sampling rates. A comparison was made of the developmental rates between constant and cyclic temperatures in winter and summer temperature regimes in south-western Australia. Developmental times for 90% of first stage larvae to emerge as adult flies are: summer constant, 21.6 days, summer cyclic, 23.5 days, winter constant 64.5 days and winter cyclic, 48.3 days. These data will allow forensic entomologists to make more accurate determinations of post-mortem intervals in cases where H. rostrata life history stages are present.