Whilst the hot weather is already actually cooling off a little from July, you won't really notice this on a trip to Santorini in August. Temperatures are still a toasty 72-81°F(22-27°C) despite not reaching last month's average highs and sunshine hours per day are still twelve on average despite being an hour less than July brought. Seawater temperatures, however, are at their annual maximum: 75°F/24°C. And there is still almost no chance of even a drop of rain.
As with other warm weather months, the island can be affected by the Meltemi throughout August. This is a wind from the north blowing persistently for up to several days at a time and is liable to make the air feel cooler: good because it injects some freshness into an otherwise sweltering summer but bad because it can make the sea very choppy.
For more on weather this month, see Greece in August: Travel Tips, Weather, & More.
Crowds & Costs
Yes, the weather is glorious, but fortunately or unfortunately (depending on your tastes) many thousands of other visitors have latched onto that fact where Santorini is concerned, and on an average August day, what with this also being the time families take their holidays, you can be forgiven for thinking half of Northern Europe is visiting the island. Now, just as for the last two months, this is high season, and costs for everything on the island will be as high as they get all year.
It will be likely more crowded this month even when compared to July. This means it will take you longer to explore Fira or Oia's time-lost streets, longer to find that restaurant table with the perfect sea view and longer to take that perfect holiday snapshot as you first wait for dozens of tourists to finish wandering through your photo frame.
Where to Go
In this hot, sticky and densely crowded month, you are sure to crave chilling out on one of the island's beaches, the majority of which are strung out along Santorini's east coast. Kamari is a popular black sand beach with a hotel directly leading onto the sand; other sandy beaches with hotels close by include Perissa and Perivolos. A visit to the famously striking Red Beach, comprised of small red stones and appearing to glow red in the sun, should be on your itinerary too, as should the long and lovely Baxedes Beach near Oia.
Traveling out to the far southwestern end of the island, around Akrotiri Lighthouse, is one of several ways to lose many of the crowds. Here, there are some less frequented beaches, namely Kambia Beach, White Beach, and Black Beach. Another chance to beat the crowds presents itself with a ferry ride across the island snugly in the middle of Santorini's caldera bay: rugged Thirasia, with some wonderful hiking and an ancient monastery to check out.
What to Do
It would be just common sense to gravitate to one of the island's many gorgeous beaches, sunbathing until the heat gets too much and then sliding into to the azure waters that surround Santorini's coastline. This is your holiday, after all.
If you desire any sort of peace and quiet you will have to head away from the main beaches, however, as with big hotels close by these will likely be crowded from early morning to night. You could try sea kayaking, too, checking out the awe-inspiring caldera along the west coast of Santorini in the process, or even take a cruise around the entire island including the caldera.
Too much sea and beach time? The island's culture is much celebrated too, and here, it is perhaps the viticultural and archaeological heritage that most stand out. Visit one of the wineries just a short distance south of Fira: many offer tours and tastings afterward, making for a great way to take a break from the fierce sun. Start with Santo Wines near Pyrgos, or the Koutsoyannopoulos Wine Museum outside Fira, which being uniquely located in a cave, remains cool even now.
To discover more about the archaeology here, take the trip out to the ancient Minoan city of Akrotiri in the island's southwest. This phenomenal and quite extensive ruin is sometimes referred to as the “Pompeii of the Aegean,” with good reason. Its structures are impressively intact and have yielded extensive pottery finds. There are also frescoes, and a complex drainage system illustrating just how advanced this civilization was for its time.
If you are tempted to do activities away from the water, like hiking one of the island's trails, it's going to be a very hot endeavor right now. However, it's one sure way to beat the crowds because everyone else will be at the beach.
Feast day of the Assumption of Virgin Mary August 15. This one is celebrated in Akrotiri, Firostefani and indeed most island villages. The biggest celebration is in the church of Panagia Episkopi. Preparations start one day before with traditional food and local wine which all the locals partake of with plenty of merriment.