Most shops and services are open Monday to Friday 9am to 7pm, and Saturday 9am to 2pm. They may close at some point during the day for between one and five hours - as a rule the further north you go, the longer the midday break or siesta, sometimes offset by later closing times in the evening, especially in the summer. Supermarkets seldom close during the day and are generally open much later, often until 8 or even 10pm, and on Saturday afternoons. Large shopping malls don't close before 10pm and their food and drink sections ( patios de comida ) may stay open as late as midnight. Many of them open on Sundays, too. Banks tend to be open only on weekdays, from 10am to 4pm, but casas de cambio more or less follow shop hours. However, in the Northeast, bank opening hours tend to be more like 7am-noon, to avoid the hot, steamy afternoons.

Museums are a law unto themselves, each one having its own timetable, but most close on Mondays. Legally, they are supposed to be free of charge at least one day a week; since that day varies you might like to plan your visits to different museums accordingly. Several Buenos Aires museums are closed for at least a month in the summer. Tourist offices seem to be forever adjusting their opening times, but the trend is towards longer hours and opening daily (some still close on Sundays). Don't bank on finding them open late in the evening or at weekends, especially off season or off the beaten track, though some have surprisingly long hours. Post offices' hours seldom vary from the standard 8am to 8pm on weekdays, with siestas in the hottest places, and 9am to 1pm on Saturdays, but check individual listings for exceptions. Government offices keep to an 8am to 5pm schedule, with a few variations.