Effective control of Chrysomya rufifacies (Macquart) (Diptera: Calliphoridae), a blow fly species of medical and forensic importance, requires information on seasonal prevalence and bionomics. Therefore, daily and seasonal activity patterns of C. rufifacies were studied in 3 locations representing different microhabitats (palm plantation, forested area, longan orchard) in a suburban area of Chiang Mai Province, northern Thailand. Investigations were conducted hourly for 24 h using a semi-automatic trap baited with 1–d-old beef offal (300 g). Collections were carried out twice per mo from Jul 2013 to Jun 2014. A total of 55,966 adult C. rufifacies were collected, with 52.4% of individuals trapped in the forested area. Chrysomya rufifacies was present in collections throughout the yr with peak abundance in summer. This species was active during the d with peak activity in late afternoon (3:00 to 6:00 PM). Fly abundance in traps was positively correlated with temperature (r = 0.391; P < 0.001) but negatively correlated with relative humidity (r = −0.388; P < 0.001). Female flies were more abundant in collections (0.26 male per female sex ratio), with 80% of individuals being nongravid. The baseline information provided by our study suggests that C. rufifacies is well-adapted to variable climatic conditions present in northern Thailand, specifically suburban Chiang Mai Province.