20th and 23rd June, depending on the Earth's rotation around the Sun.
In the northern hemisphere the summer solstice or mid-summer is halfway between Beltane (1st May) and Lughnassadh (1st August).
In the Southern Hemisphere this date is between 20th and 23rd December.
This day indicates in the Northern Hemisphere when the daylight hours are longest. Litha has been celebrated since ancient times and is the opposite of Yule, the shortest day of the year in the Northern Hemisphere.
Litha celebrates abundance, fertility, and all the riches of nature in full bloom. During this time the veils between the worlds are thin and communication with the spirits of nature happens more often.
This is also a time for handfasting or weddings. and for communication with the spirits of Nature. At Litha, the portals between "the fields we know" and the worlds beyond stand open. This is an excellent time for rites of divination.
People who celebrate Litha wear garlands of flowers, including the yellow blossoms of St. John's Wort. In ancient times the Litha rites included morris dancing, singing, storytelling, pageantry and feasting. The whole community participated and had a village bonfire and torch lit processions through the villages after dark.
People believed that the Litha bonfires were quite powerful, and that you could gain prosperity and protection for yourself and your clan by jumping over the Litha bonfire. Courting couples would also join hands and jump over the embers of the Litha fire three times to ensure a long and happy marriage, financial prosperity and many children. People used the embers of the Litha bonfire as protection against injury and bad weather in harvest time.