text: when is the first day of summer?   it all depends on which summer you're referring to.  the season begins on the 21st of june in the northern hemisphere while it begins december 21st in the southern hemisphere.  while for my oldest son, as well as many other children in the area, summer begins with the end of their school day on the 30th of june.  for me, summer is when summer ice begins and i begin to work hockey camps for kids to adults in early july.  and to others, summer begins when it gets hot outside.  to many, it already is summer.