365-day calendar 365-day calendar A 365-day calendar consists of exactly 365 days per year (no leap days), and is primarily used in computer models and as an assumption in every-day calculations. For example, a calculation of a daily rate may use an annual total divided by exactly 365. Interest rates in some banks are calculated using a 365-day calendar. Some Mesoamerican calendars used a 365-day year with no leap year, resulting in a gradual shift of the seasons relative to the calendar. This includes the Maya Haab' and the Aztec Xiuhpohualli calendars. Some versions of the Zoroastrian calendar also use a fixed
Adoption of the Gregorian calendar No. 28 of Month 1 () On the other hand, people never call dates on the Chinese calendar as "No. "dd".", which avoids any possible ambiguity. When referencing dates before the introduction of the Gregorian calendar in 1582, the official Chinese calendar may either inherit the issues with earlier calendars to be historically correct or follow the proleptic Gregorian calendar if so specified. The Islamic calendar is a lunar one, so that there are twelve lunar months in a year of 354 or 355 days, being 11 days shorter than a solar year. Consequently, holy days in Islam migrate around