Learn the lunar cycle and 2026 moon phases, including new moon, full moon, and quarter phases. Discover dates, illumination, and tidal effects from NASA and Space.com.

What is the moon phase today? Today, Dec. 29, 2025, the moon is 9 days old and is in the Waxing Gibbous phase of its lunar cycle. It is 74% illuminated. Moon phase Date Full Moon Dec. 4 Third/Last ...