The time of drinking in terms of daytime versus evening and weekday versus weekend is charted for regular drinkers in 14 countries in Europe, Asia, Latin America, Africa and Oceania.National or regional adult population surveys from the GENACIS project.The weekly rhythm of drinking varies greatly between societies. Drinking was generally more likely after 5 p.m. and on weekends. To this extent, alcohol consumption is now regulated by a universal clock. The relation of time of day and of the week of drinking to problems from drinking varied between societies. Drinking at specific times was more likely to predict problems among men than women, though for men the particular time varied, while weekday evenings were the most problematic time for women. The relation of drinking at a particular time to problems in part reflected that heavy drinkers were more likely to be drinking at that time.There are commonalities across cultures in drinking by time of day and day of the week, but the implications of the timing for alcohol-related problems are fairly culture-specific.