Today is the Summer Solstice. The summer solstice — the annual moment at which the sun is the highest it ever gets in the sky — occurs today at 3:34PM PT. This time also marks the beginning of astronomical summer in the Northern Hemisphere.
The last time the June full moon, sometimes called the "strawberry moon," and the summer solstice fell on the same day was 1948.
PS: The reason for the 3.17 was the photo was taken that day in 2010.