Best way to visit Greek islands
The best time to visit Santorini is the fall when the weather is warm and the crowds are few. Like all of the Cyclades, Santorini welcomes the most visitors during the summer, so you'll need to make your reservations at least two months in advance if you plan on visiting anytime from June through August. Looking for a bargain? Try winter when room rates tend to plummet. Keep in mind, thought, that this season's average highs only reach the 50s (not good for sunbathing) and the region sees plenty of precipitation. However, all that rain does make for a very flowery (and warm) spring season. Crowds will be at a low in the spring as well, though plenty of tourists begin invading the islands come May.
The tourist season starts around Easter each year, and predominantly Greek and European visitors begin their island pilgrimages at this time. Keep in mind that Easter itself can be quite busy. The temperatures are mild, hovering between the 60s and 70s for most of the spring months. While it may still be a bit too cold to don a swimsuit, you'll find that the weather is perfect for sightseeing. Be sure to bring a warm jacket for the cool evenings.
The summer marks Santorini's peak season, as well as the best weather for swimming. Visitors flock to the area in search of the perfect beach vacation. If you decide to brave the heavy crowds, make sure to book your hotel at least two months in advance to ensure availability.
The Aegean water is still warm in September and October, most days are sunny, and daytime temperatures typically hover in the 70s and 80s. Most of the tourist infrastructure is still open for business — despite the thinning crowds. This is also a great time to explore Santorini's historical sites and natural wonders. And thankfully, fewer crowds cause room rates to drop. Beware, however, that some restaurants, hotels and other establishments begin to close for the season in late October or early November and won't reopen until spring.
This is the least popular time to visit Santorini thanks to temperatures in the 50s — hardly pleasant for sunbathing. The wintertime also sees the most precipitation, which trumpets forth a blossom-filled spring. You can find great deals in the off-season, but consider the downsides of less pleasant weather and many closed tourist hot spots.