Objectives To examine hot flashes in relation to climate and activity patterns, and to compare subjective and objective hot flashes among Bangladeshi immigrants to London, their white London neighbors, and women still living in their community of origin, Sylhet, Bangladesh (“sedentees”). Methods Ninety‐five women, aged 40–55, wore the Biolog ambulatory hot flash monitor. Objective measurements and subjective hot flash reports were examined in relation to demographic, reproductive, anthropometric, and lifestyle variables; temperature and humidity at 12:00 and 18:00; and time spent on housework and cooking. Concordance of objective and subjective hot flashes was assessed by Kappa statistics and by sensitivity of hot flash classification. Results During the study period, Bangladeshi sedentees reported more subjective hot flashes (p < .05), but there was no difference in number of objective hot flashes. White Londoners were more likely to describe hot flashes on their face and neck compared to Bangladeshis (p < .05). Sedentees were more likely to describe hot flashes on their feet (p < .05). Postmenopausal status, increasing parity, and high levels of housework were significant determinants of subjective hot flashes, while ambient temperature and humidity were not. Measures of subjective/objective concordance were low but similar across groups (10–20%). The proportion of objective hot flashes that were also self‐reported was lowest among immigrants. Discussion Hot flashes were not associated with warmer temperatures, but were associated with housework and with site‐specific patterns of cooking. The number of objective hot flash measures did not differ, but differences in subjective experience suggest the influence of culture.