Academic term
In most countries, the academic year begins in late summer or early autumn and ends during the following spring or summer. In Northern Hemisphere countries, this means that the academic year lasts from August, September, or October to May, June, or July. In Southern Hemisphere countries, the academic year aligns with the calendar year, lasting from February or March to November or December. The summer may or may not be part of the term system.
Diplom
At the time of the Bologna process, schools in most German states started changing from 13 school years to 12 years. (An exception are the states of Saxony and Thuringia, where Gymnasium has always lasted only 12 years ever since the German Reunification.) Most of the students going for a "Diplom" therefore spent 13 years in school before starting their university studies, while the younger Bachelor students nowadays may start one year earlier. (However, in some states, such as Rhineland-Palatinate or Schleswig-Holstein, the first class which completes school after 12 years will graduate as late as 2016.) Regarding international comparison, one may argue that British, Irish and French high school students have school also in the afternoons which could compensate with the (former) additional year of school attendance in Germany.
Note: For the Diplom (FH) a student has to spend one to two obligatory semesters during his studies in a company. These semesters are included in the table. The study time is therefore one to two semesters shorter. Bachelor studies have them included in the table too. For the Diplom (Universität) those semesters are sometimes not included in the table.