Find full moon dates at MoonGiant.com and Space.com. These website feature calendars listing moon phases as observed from the United States, as well as moon phase calculators, which allow users to input their locations to display the peak time for observing a full moon or other lunar phase.
MoonGiant.com features a unique interactive visual aid on its main page depicting the lunar phase on a user-selected date and time. Click the back and forward arrows near the top-right of the page to watch how incremental changes in the date or time affect the moon's phase, or click the Full Moon Calendar link about midway down the right side of the page to display a list of dates of upcoming full moons and new moons.
Click the Moon Details button near the top-left of the page to display an image of the current moon phase along with details such as the moon's illumination level, distance from Earth and angle relative to the Sun. Click a date on the calendar to display an image of the lunar phase on that date, or click the Moon Phases Calendar tab near the top of the page to display images of lunar phases for each day for the coming month.
In addition to its annual Full Moon Calendar, Space.com features articles and videos about moon phases and their causes, lunar eclipses, solar eclipses, telescope usage and many other topics related to skywatching. Its Skywatching Guide features a chronological guide to major skywatching events, such as moon phases, planetary alignments and eclipses and alerts readers to unexpected astronomical events, such as major solar flares and sunspots.
During the full moon phase the side facing the earth is almost completely illuminated by the sun, giving it the appearance of a full disc. At other phases the moon is partially obscured by a shadow cast by the earth onto the moon's surface. This causes the moon to appear as other shapes, such as a half-disc or crescent. A full moon occurs once every four weeks, which makes it possible for some months to have two full moons.