Why is the first day of summer not the hotest day of the year

Question

the is the closest to the eart that day, so why is it usuaaly colder in July and aug and also why is the first day of winter not the coldest

Answer 1

There is a lag effect between when the individual hemispheres of the Earth  (north and south) receive their greatest and least amount of incoming solar energy, and when the Earth/atmosphere system responds to those changes.  Just like the coolest time of day is typically around sunrise, while the warmest time of day is in the late afternoon,  the overall warmest temperatures on average occur not at the summer solstice, but about 4 to 6 weeks after the solstice.  And likewise, the coldest time of year on average is not at the winter solstice, but again about 4 to 6 weeks later.