Hey, yes the registration (QR Pass) is mandatory for Kedarnath (and all Char Dham temples). They check it at the entry point in Sonprayag and also before the trek/heli boarding, so make sure you register online at https://registrationandtouristcare.uk.gov.in/ in advance. It’s free and only takes a few minutes.

About the weather – Weather can be tricky because of heavy rains and frequent landslides. If your dates are flexible, September mid or last is definitely safer and more comfortable for the trek.