NEVER
On average, a total lunar eclipse can be observed from somewhere on Earth about every 2.5 years. However, the visibility of a lunar eclipse in the US can vary depending on the specific location and timing of the eclipse.
One may occur when the moon is full. A Lunar eclipse happens when the sun moon and earth are all lined up, with earth in between the sun and the moon. At this position, with the sun behind us and the moon in front of us, we see a full moon, as the light is reflected back of the surface. The lunar eclipse happens when the earths shadow can be seen on the moon. We don't always get a Lunar eclipse when there is a full moon though, as we don't often get a perfect enough line up. This is due to the orbits of the Earth and moon not being perfectly flat.
There will be a partial lunar eclipse on June 26, 2010, which will be visible from the west coast of the US, from Australia, and from Japan and the eastern part of Asia. There will be a total lunar eclipse on December 21, 2010, which will (weather permitting!) be visible from anyplace in North America.
There was a total lunar eclipse visible throughout the US on February 21, 2008.
The next penumbral lunar eclipse that will be visible from the U.S will be on October 18th 2013. This penumbral lunar eclipse will also be visible from Europe, Africa, and Asia.
the moon
There will be a total lunar eclipse on December 21, 2010, which will (weather permitting!) be visible from anywhere in North America.
The earth
Solar eclipse (total or otherwise): at new moon. Lunar eclipse (total or otherwise): at full moon. -- Immediately after a Solar eclipse you get a new crescent moon appearing in the sky. Obviously therefore the eclipse happens at the point when the side of the moon that faces us is in total shadow - indeed during the eclipse we are covered by that shadow. -- Immediately after a lunar eclipse, as soon as the moon moves out of the shadow, it is full.
yes but it's a cloudy night
They happen during, and only during, the new moon. This is because during an eclipse the moon has the sun shining from directly behind it, and it's impossible for us to see any of the side of the moon lit up by the sun from this angle.
This is because the Moon needs to be blocking the source of light provided to us, this source is the Sun. The 'new moon' is the first phase where there is almost no visible moon. The 'full moon' is where you can see the whole moon. To cause a solar eclipse, the moon needs to be in the line of the Earth and the Sun, and to cause a Lunar eclipse, the Earth needs to be in the line of the Sun and the Moon. Sun-Moon-Earth = Solar Eclipse Sun-Earth-Moon = Lunar Eclipse