Yes this is best time to travel to Greece, from Late April to November the weather is great and there’s little rain. The sea temperature warms throughout the summer and swimming is best in July, August, and September. August is the busiest and most expensive month but is the best for nightlife and partying. Crete and Santorini are also appealing in April and November (since they have more to see and do than most islands). Athens is best from March to June and September to November.
Hello Sanika, The best time would be to travel before October actually if you want to travel to Santorini. Normally if you are including Santorini in your itinerary then Mid October onwards there are few things which gets closed. Like I was not able to visit to White Sand Beech in Santorini because you can only reach via boat there and the boats stops operating starting 01st October. Rest you also will not get much options related to food during this time. If Santorini isn't on your list and if you are talking about Athens and all, then it is the best time to visit because most of the ticket cost gets reduced to half. Feel Free to reach out to me if you need more answers I have an ongoing series about Greece you can follow here