All of them
The Gregorian Calendar is solar and the Hebrew Calendar is lunisolar.
The United States uses the Gregorian calendar, which is a solar calendar.
The Gregorian calendar is the most widely used civil calendar worldwide. It was introduced by Pope Gregory XIII in 1582 to correct inaccuracies in the Julian calendar. The Gregorian calendar is a solar calendar that is divided into 12 months with varying lengths to match the solar year.
The Julian calendar was replaced by the Gregorian calendar to address inaccuracies in the calculation of leap years. The Gregorian calendar introduced a more precise leap year rule to better align the calendar year with the solar year, reducing the discrepancies that had accumulated over time.
The term "synchronize" is unclear. The Islamic Calendar has a year of only 354 days, so it can never be the same length as a solar year (usually calculated with the Gregorian Calendar with an average of years length of 365.24 days). However, the date on the Islamic Calendar and on the Gregorian Calendar will correlate every 34 Islamic Calendar Years which correspond to 33 Gregorian Calendar Years.
The Gregorian calendar is a solar calender, that was first used in 1582. This is where the start of leap year came into play. This is also how they began to determine the date of Easter.
The Gregorian calendar is a purely solar calendar, while the Jewish calendar is a solar-lunar calendar. In a bit more detail, the Gregorian calendar has months that have nothing to do with the moon and a leap day is added in February every few years to keep the days and months in their right season. In the Jewish calendar, every month starts with the new moon and a leap month is inserted (by doubling the spring month of Adar) when needed to keep the months in their right season.
The Gregorian calendar is a solar calendar based on the Earth's orbit around the Sun, with months of fixed lengths. The lunar calendar is based on the cycles of the Moon and has months of varying lengths, making it around 11 days shorter than the Gregorian calendar year. This leads to differences in how dates are calculated and the timing of religious or cultural events.
Hanukkah always starts on the 25th day of Kislev on the Jewish calendar. This date corresponds to sometime in December on the Gregorian calendar. The reason it varies is because the Jewish calendar is based on the lunar cycles and the Gregorian calendar is based on the solar cycles.
The Jewish calendar consists of twelve lunar months. It also keeps in step with the solar year, by adding a thirteenth lunar leap-month seven times every nineteen years. The Gregorian calendar, which sticks to the solar year, ignores the lunar months and does not attempt to keep in step with them.
The Jewish calendar consists of twelve lunar months. It also keeps in step with the solar year, by adding a thirteenth lunar leap-month seven times every nineteen years. The Gregorian calendar, which sticks to the solar year, ignores the lunar months and does not attempt to keep in step with them.
Although the Gregorian calendar has "months", it is not in any way governed by the phases of the moon. It is strictly a solar calendar, so its emphasis is to remain in sync with the solstices and equinoxes, the characteristics of the Earth's orbit of the sun. Only lunar calendars, like the Muslim calendar, and lunisolar calendars, like the Jewish calendar, are based on the phases of the moon, with each month beginning at the time of the new moon.