According to the folk calendar - Fedot the Guardian

Fedot the Guardian according to the folk calendar is celebrated on June 20 (June 7 according to the old style). The holiday was named Fedot in honor of Saint Theodotus of Ancyra, revered by Orthodox believers on this day. Theodotus was from Ankyra (modern Ankara, Turkey), believed in the Lord and helped Christians who suffered at the hands of idolaters. When the pagans drowned seven Christian women, he took out their bodies and buried them with honor. Having learned about his act, the ruler ordered Theodotus to be punished: he was beaten and tortured, forcing him to renounce God. The saint stood firm, glorifying Christ, then his head was cut off. The people called Fedot the Guardian, because they believed that on this day he guarded the inhabitants of the reservoir from attacks by mermaids. On his day, peasants boldly went to swim in a river or lake, having first prayed to Saint Theodotus. It was believed that the saint was near a pond with a pointed sickle, and if the undine suddenly wanted to lure a guy or girl into the water, Fedot would immediately cut off her hair. The mermaid had all her power and witchcraft in her hair, and, having lost it, she became helpless. The grain harvest was determined on Fedot Day. The peasants always eagerly awaited rain, but rainfall on Fetod the Guardian meant an empty ear in the grain crops. A sunny day made the residents happy because it helped the ears to fill, which means they predicted a lot of grain when harvested. They prayed to Saint Theodotus for a generous harvest in the fields. By this day, the period was approaching when the sowing of cereal crops was ending, and it was still too early to mow hay. Then the men did the repairs around the house, and the women did the big laundry. They washed everything that had accumulated - from sheets to underwear. They were boiled in a vat over a fire, and lye was used to remove dirt. They rinsed the clothes in ponds, then dried them and ironed them with charcoal irons. If peals of thunder were heard at Fedot the Guardian, then they prepared for bad weather over the next days. Also, bad days awaited at the sight of smoke swirling across the ground. Sparrows swimming in a puddle promised the arrival of heat, and in the ground - rain. Reddish flashes of lightning on the horizon were observed in windy and hurricane weather.