Sign of light

As I biked home tonight, I came across this festive sign by the lakes. I wouldn't want to sunbathe by the lakes, nor swim in them, no matter what season, but tonight it looked like it was filled with slush-ice. Brrrrr. I wonder what the sign is refering to. I saw something to the right, but my fingers were freezing so hard, I just had to continue on home, not exploring the scenary.
Anyway, it made me think of the cover of Düreforsögs 'Beach' that two of my friends made nearly a year ago.

Love,
Ida