A growing body of evidence suggests that dengue infection in Singapore predominantly occurs away from the home, but when and where dengue transmission occurs is unclear, confounding control efforts. The authors' estimate days of the week in which dengue inpatients in Singapore were infected during the period 2006-2008, based on the day they became febrile and historical data on the incubation period, using Bayesian statistical methods. Among male inpatients, the relative risk of infection is an estimated 57% higher at the weekend, suggesting infections associated with the home or leisure activities. There was no evidence of elevated risk of infection at the weekend for female inpatients. The study motivates further research identifying locales frequented in the week leading up to onset to improve the effective targeting of vector control efforts.