gen-define-the-lunar-versus-solar-calendar-and-give-one-short-wo-c026

Define the lunar versus solar calendar and give one short worked example.

# Lunar vs Solar Calendars ## **Lunar Calendar** Based on the **phases of the Moon**. One month = one complete lunar cycle (new moon to new moon) ≈ **29.5 days**. A lunar year has 12 months ≈ **354 days**. ## **Solar Calendar** Based on **Earth's orbit around the Sun**. One year = time for Earth to complete one orbit ≈ **365.25 days**. Months are arbitrary divisions. ## **Key Difference** A lunar year is ~11 days shorter than a solar year, so lunar calendars drift relative to seasons. --- ## **Worked Example: Islamic Calendar (Lunar)** The Islamic calendar is purely lunar. If Ramadan begins on **January 1, 2024**: - Lunar year = 354 days - Solar year = 365 days - Difference = 11 days **When will Ramadan start in 2025?** January 1, 2024 − 11 days = **December 21, 2024** Over time, Ramadan "moves backward" through the solar year, cycling through all seasons over approximately 33 years. *(In contrast, the Gregorian solar calendar keeps months fixed to seasons—January is always winter in the Northern Hemisphere.)*