Yes, it does.
In most of Europe and South America the working week starts on Monday.
I can answer you the same thing: why does your calendar start with Sunday? You start your week on Monday, right? You go to your job on Monday, not Sunday. So it doesn't make any sense that your week calendar starts on Sunday.
Monday (lunes) precedes Tuesday (martes) in the Spanish calendar.
monday
The US standard of Sunday as the first day of the week is not observed in much of Europe, with Monday (lunes) often the first day of the calendar week. This is also the ISO standard 8601.
The Spanish calendar, like most Western calendars, starts on January 1st. This date marks the beginning of the new year and is celebrated with various festivities. Additionally, the workweek in Spain typically begins on Monday, aligning with the standard practice in many European countries.
The French consider the week to start on Monday, but this is simply a calendar convention just as the American week starting on Sunday is a calendar convention. It does not change any dates or the work-week (which is still Monday-Friday).
The French calendar starts on a Monday due to the influence of the ISO 8601 standard, which designates Monday as the first day of the week. This choice aligns with many European countries and reflects a cultural preference for organizing the workweek. Additionally, starting the week on a Monday helps to provide a clear distinction between weekdays and the weekend. The French Revolution also contributed to various reforms in calendar systems, but the Monday-start convention has persisted.
'Calendar' in Spanish is 'calendario'.
Calendar, in Spanish, is "calendario".
The US standard of Sunday as the first day of the week is not observed in much of Europe, with Monday (lunes) often the first day of the calendar week.
The French week starts on Monday (lundi) and ends on Sunday (dimanche).