In a normal year, April would be too early. Even into May. This year, much less snow than usual for this time of year, comparable to middle of May in a normal year.
However, the problem has more often to do with drifts in specific shaded locations, rather than total snow cover. These block the trails that go up or cross the ravines (now full of snow). Snow drifts can ice over and be very treacherous to cross, almost impossible without the right gear. There are one or two such places on the Potamos/Zaranokefala/Ag Ioannis route.
Everyone has this sort of problem every year. It's generally not a good idea to go into the mountains with one and only one plan, with the psychological risk of doing it all all costs. The solution is to go with 2-3 hiking alternatives. When there, look at the mountain and decide what the best/safest option is. The weather may not cooperate. Contact Kallergi hut and ask for day by day specifics. Another contact option is one of the hotels at Omalos .. they may or may not be open this early. Neos Omalos Hotel might be a good source of info. Send an email and ask.
