Kurdish calendar by a leap year every fourth year. It starts with the exact first day of spring according to the Gregorian calendar (March 20 or 21). Like the Gregorian system, the Kurdish calendar divides the year into four seasons: Buhar, Tawistan or Hawín, Payiz and Zimistan. It divides the year into 12 months, each month into four weeks and every week into seven days. In the Kurdish calendar the first six months (comprising spring and summer) are each 31 days long, while the next five months (in fall and winter) are 30 days each. The last winter month, the 12th month
Adoption of the Gregorian calendar the solar year on a 32-year cycle. Some countries in the Islamic world use the Gregorian calendar for civil purposes, while retaining the Islamic calendar for religious purposes. Saudi Arabia adopted the Gregorian calendar as its civil calendar at the end of 2016. Today, the vast majority of countries use the Gregorian calendar as their sole civil calendar. Countries which have not adopted the Gregorian calendar are Ethiopia (Ethiopian calendar), Iran and Afghanistan (Persian calendar). Some countries use other calendars alongside the Gregorian calendar, including India (Indian national calendar), Bangladesh (Bengali calendar), Nepal (Vikram Samvat), Pakistan (Islamic calendar), Israel (Hebrew