When is it correct the use of that to introduce information in a sentence?

Question

For example in Spanish we say ' Lo mejor que ha sucedido ultimamente es que ha nevado por primera vez en 90 años'
If I want to say that in English, shall I say' the best thing (that) has happened lately is (that) has snowed for the first time in the last 90 years.'

Answer 1

I don't know Spanish, but in English you would need both of the "that"s you have in brackets. You also need "it" before "has snowed".

Answer 2

The best thing to have happened of late is that it has snowed for the first time in 90 years.