george wrote:
Are you required to have time up night flying to do a PPL in the US ?

With the exception of those receiving flight training in Alaska, yes.

Even for those in Alaska, a private pilot certificate could be issued with
a limitation that night flying is prohibited - and the person would be
required to get night training within 12 months or the certificate would
become invalid. The rationale appears to be that training during the summer
at high latitudes yields insufficient night hours.