There was a very hot summer the year When he was born
why you didn't translit it like this::
There was a very hot summer when he was born
also, when
you can put it in the 1st of the sentence
it is not a rule to put it in the second section
so you can say::
When he was born,it was a very hot summer.
so the (,) is so important in this case
thanx 4 the lesson