ryanair's conditions state:-
"If your flight is cancelled or before the date of travel, is rescheduled so as to depart more than three hours before or after the original departure time then you will be entitled to a travel credit or full refund of all monies paid if the alternative flight/s offered are not suitable to you and you do not travel.
Ryanair does not provide compensation for flights which are delayed or cancelled for reasons beyond Ryanair's control. You may therefore wish to ensure that you have suitable private insurance cover in force to cover such eventualities. Your rights under EU Regulation 261/2004 are unaffected, so in the case of denied boarding, flight cancellation or a delay in excess of two hours you will be provided with a written notice setting out the rules for compensation and assistance in line with such Regulation."
It would appear that delays etc at Rome today were caused by fog, ie outside Ryanair's control. When I had a flight from Tours cancelled due to an Air Traffic Control strike, I requested, and got, a credit card refund over the phone.