The school announced that pupils are not expected to attend tomorrow, but urged Year 11 and 13 to make a concerted effort to do so ahead of their GCSE and A Level examinations with certain exam boards still running them.
Prep pupils are also encouraged to attend and pick up any work needed during the closure.
Teaching and support staff will be in school as normal until the end of the week, with a further announcement regarding plans expected on Friday.
All teaching staff have been briefed and preparing for the need to provide online learning packages.
Rydal Penrhos is awaiting further guidance regarding upcoming examinations, but are requesting “all pupils continue as normal with their preparations and revision” despite Qualifications Wales and the WJEC cancelling their examinations later this year.
This comes after Welsh Education Minister Kirstie Williams confirmed that all schools in Wales are to shut by Friday at the latest.
The announcement was made almost simultaneously with the Scottish Government's decision that schools are expected to shut by the end of the week.
The timeframe of the closure has not been confirmed.
Rydal Penrhos has already offered willingness to provide care for the children of frontline workers to Conwy county council.
This provision will be coordinated by the Local Authority and the school is liaising with council officials as to what assistance they can provide in the coming weeks and, in particular, during the upcoming Easter Holiday period.
John Waszek, Executive Principal of Rydal Penrhos, said: “We are very keen to do our bit to aid the community and Conwy county council during this unprecedented pandemic.
“Many of our prep and senior school parents work for the National Health Service and we have informed the council that Rydal Penrhos is willing to do whatever we can to help during this trying time.”