How Imbolc Became St. Brigit’s Day 
Groundhog Day is an annual American tradition of predicting the end of winter.
Each year, the groundhog emerges from his hole in the ground. If it’s cloudy and the groundhog can’t see his shadow, then spring will come early.
If it’s sunny though, the groundhog will see its shadow and retreat back into its burrow. Therefore, the winter weather will continue for six more weeks.
But what was the original meaning and purpose of this day?
Imbolc began as an Irish Gaelic festival, marking the beginning of spring.
The four Gaelic seasonal festivals are Imbolc (February 1), Beltane (May 1), Lughnasadh (August 1), and Samhain (November 1).
Each occurs on cross quarter days, which occur halfway between each solstice and equinox.
Imbolc was celebrated on February 1st, the day halfway between the winter solstice and spring equinox.
The holiday was a celebration of the birth of spring and the longer days . Celebrations often involved fires and special foods including butter, milk, and bannocks (pancakes).
Fire and purification were an important part of the festival. Candles and fires represented the return of warmth in the coming months. Holy wells were also visited, and people used their water to bless objects.
The festival also included divination, or looking for signs of the future. The Irish believed that Imbolc was when a mythical old woman named Cailleach gathered her firewood for the rest of the winter.
The legend was that if she wished to make the winter last longer, she would make sure the weather on Imbolc was bright and sunny, so she could gather plenty of firewood.
Therefore, the Irish were relieved if Imbolc was a dark, cloudy day, since Cailleach was asleep and winter was almost over.
Saint Brigid
After Saint Brigid died in 524, Imbolc was celebrated as her feast day. She was an Irish Catholic nun, also known as “Mary of the Gael”, honored as one of the patron saints of Ireland.
The Irish had a special feast on Imbolc Eve to mark the end of winter. Often, food and drink would be set aside for Brigit.
Before going to bed, clothes and strips of cloth were left outside for Brigid to bless. Ashes from the fire would be raked smooth and in the morning, they would look for some kind of mark on the ashes as a sign that Brigid had visited. The clothes or strips of cloth would be brought inside, and believed to have power of healing and protection.
Irish girls and young women used twigs and thick grass to make a Brídeóg (a doll of Brigid, also known as a “Breedhoge” or “Biddy”). They decorated them with cloth, shells and flowers.
They would carry the doll in a procession while singing a hymn to Brigid. They wore white with their hair down as a symbol of purity. They visited every house in the area, where they received food or more decoration for their Brídeóg.
Afterwards, they had a special feast with the Brídeóg in a place of honor, then put it to bed with lullabies. When the meal was finished, boys and young men visited and humbly asked for admission to see the Brídeóg. They stayed and joined the girls in dancing until dawn.
They also made Brigit’s Cross, which was thick grass “woven into a shape similar to a swastika”, with a square in the middle and four arms extending from each corner.
These crosses were placed throughout Irish homes to welcome Brigid and protect the buildings from fire and lightning. They were often left there until the next year’s celebration.
Some people throughout Europe still make these crosses and keep these sacred traditions alive.
H/T https://jettandjahn.com/2013/02/the-irish-origin-of-groundhog-day/
Read more about the Feast of St Brigid here