Litha is the name of a Midsummer holiday and may refer to the period of time centered upon the summer solstice and the diverse celebrations of it around the Northern Hemisphere, but more often refers to European celebrations that accompany the summer solstice, or to Western festivals that take place in June and are usually related to Saint John the Baptist. European midsummer-related holidays, traditions and celebrations, many of which are pre-Christian in origin (although they are also called Saint John's Day festivals), are particularly important in Latvia, Lithuania, Norway, Denmark, Sweden, Finland and Estonia, but found also in Ireland, parts of Britain (Cornwall especially), France, Italy, Portugal, Spain, in other parts of Europe and elsewhere, such as Canada, the United States, and even in the Southern Hemisphere (Brazil), where this European-born celebration would be more appropriately called Midwinter.
Solstitial celebrations still centre upon 24 June, which is no longer the longest day of the year. The difference between the Julian calendar year (365.2500 days) and the tropical year (365.2422 days) moved the day associated with the actual astronomical solstice forward approximately three days every four centuries until Pope Gregory XIII changed the calendar bringing the solstice to around 21 June. In the Gregorian calendar, the solstice moves around a bit but in the long term it moves only about one day in 3000 years.
As forms of Neopaganism can be quite different and have very different origins, these representations can vary considerably, despite the shared name. Some celebrate in a manner as close as possible to how they believe the Ancient Germanic pagans observed the tradition, while others observe the holiday with rituals culled from numerous other unrelated sources, Germanic culture being only one of the sources used.
Litha is one of the eight solar holidays or sabbats observed by Wiccans, though the New Forest traditions (those referred to as British Traditional Wicca) tend to use the traditional name Midsummer. It is celebrated on the Summer Solstice, or close to it. The holiday is considered the turning point at which summer reaches its height and the sun shines longest.