Personally I enjoyed visiting Sicily in April, but you do need to go prepared. It is early in the season and the weather can be unpredictable! You will see some beautiful sunny days, but you are also likely to get caught in some rain and possibly even snow if you are in the mountains, so take clothes for all seasons.
One of the major plus points is that as nowhere will be too crowded, you won’t spend your holiday standing in queues and you might even get some of the tourist sites almost to yourself. For me, that is worth the unpredictable weather. I am not a fan of sightseeing in the heat of summer, so the temperatures were perfect for me. I had plenty of sunshine but the thermometer stayed in the low 20’s.
Something else that I loved were all the wild flowers which were in bloom everywhere. All of the archeological sites were full of them and looked beautiful. Amazing photo opportunities too!
I toured the island starting at Acireale, then on to Syracuse and Noto then Modica, Ragusa and Agrigento, Selinunte and Erice, Segesta, Palermo, Cefalu and finishing in Taormina.
Both Acireale and Taormina were useful bases for seeing Mount Etna and for getting to the airport.
So if you are already planning ahead for April next year, spring is a lovely time to go!