Hello, we did this last week. It was 18 degrees and sunny at the bottom and 3 degrees at the top and so windy our DC literally could not stand up without getting blown down again!!
We read before hand to take a fleece, wool hat, wool gloves, sunglasses and sunscreen with us in backpack as well as waterproof coats. DIdn't need the sunscreen and sunglasses but we needed the gloves, hats and fleece desperately.
We did PYG up which was far too much for our DC in retrospect, Ranger or LLamberis would have been much better. LLamberis also has a cafe half way up, but its takeaway only and the loo isn't open due to covid. The cafe at the top isn't open at all, so take all you will need food and drink wise with you.
There is easy transport between the different paths called the Sherpa system. You can pay on board and board at different places. If you google it the timetables will come up but make sure you all have face coverings, they were turning away people who had just come down a mountain, were freezing cold and wet through if they didn't have one.
A lof of the car parks, eg the one at the bottom of the PYG, have just become book in advance only, you can't turn up on the day. There are 3 or 4 long stay car parks in LLamberis opposite the entrance to the railway and the Sherpa bus stops by them. There are also public loos there, in an alleyway that goes down the side of the bridge hotel.