One of the surest signs of summer splashed into action yesterday as the fountains and pools at the historic Frog Pond on Boston Common opened for the season.

The Boston Parks Department and the Skating Club of Boston welcomed enthusiastic children and families for the opening, flipping the switch on the spray pools with a kick-off celebration attended by Mayor Michelle Wu.

The opening was sponsored by Bank of America and H.P. Hood LLC, along with additional support from  LEGOLAND Discovery Center Boston, N.E. Dairy Council, and Polar Beverages.