These are from the Songkran Festival in Chiang Mai (2017 and 2018)

From Wikipedia:

The Songkran celebration is rich with symbolic traditions. Mornings begin with merit-making. Visiting local temples and offering food to the Buddhist monks is commonly practiced. On this specific occasion, performing water pouring on Buddha statues is considered an iconic ritual for this holiday. It represents purification and the washing away of one's sins and bad luck.As a festival of unity, people who have moved away usually return home to their loved ones and elders. As a way to show respect, younger people often practice water pouring over the palms of elders' hands. Paying reverence to ancestors is also an important part of Songkran tradition.

The holiday is known for its water festival which is mostly celebrated by young people. Major streets are closed to traffic, and are used as arenas for water fights. Celebrants, young and old, participate in this tradition by splashing water on each other. Traditional parades are held and in some venues "Miss Songkran" is crowned.” where contestants are clothed in traditional Thai dress.