Santorini Weather: Temperature by Month and When to Go

Wind, not heat, is the story

The mean daily maximum wind speed runs 28-37 km/h in every month of the year. From July to August the seasonal meltemi pushes the strongest days, and it is the reason caldera boats get cancelled. Every operator listing carries a weather clause for exactly this. The practical move is to book any boat early in your stay, on a departure with free cancellation up to 24 hours ahead, so a windy day costs you nothing. Our catamaran cruise guide compares the options.

Wind also shapes the beaches. The east coast at Perissa and Kamari catches the meltemi and gets surf and flying sand, while the south coast at Vlychada stays calmer behind its cliffs.

• Book boats for early in the trip, with free cancellation
• Expect choppy water on east-coast beaches in July and August
• Wind chill on the caldera rim makes a jacket useful even in May

The numbers understate the warmth

The climate record above comes from a data cell that is mostly sea, so its daytime highs read two to three degrees cooler than a thermometer on land in Fira would. Read 24°C (75°F) in June as a low-twenties day in town, warmer in sheltered caldera corners. Nights stay mild from June to September, with lows of 20-23°C, so you eat outdoors without a second thought.

The reverse holds in winter. A 13°C (56°F) January afternoon feels raw when the wind comes up the caldera walls, and most island businesses shut for the season. Hotels are cheap, though, and our cheap hotels page shows how far a winter budget goes.

Rain arrives only in winter

July records effectively no rain and August about 1 mm, which is why the island turns brown by late summer. Real rain arrives with November, December and January, at 32-60 mm a month across six to eleven rainy days. April and October sit in between, at 15-20 mm and three or four rainy days.

For sightseeing this is good news. An afternoon shower in April or October rarely spoils more than a few hours, and the roofed Akrotiri excavation is the perfect rainy-day site, buried in ash by the eruption of circa 1600 BC and now under a protective roof. Its winter hours run 08:30-15:30, closed Tuesdays.

Heat, crowds and the meltemi

July and August post highs of 26°C (79°F) in the sea-moderated record, with rain essentially absent. The heat is real in the caldera villages, where white walls bounce light and shade is scarce on the rim path. Do the Fira to Oia hike before 09:00 or after 17:00, and carry more water than feels reasonable, because the rim has almost no shade along its roughly 10 km.

This is also peak season. Sunset crowds pack Oia castle every evening, and hotel rates sit at their annual high. Our where to stay page breaks down which villages hold up best in the crush.

The meltemi is the wildcard. Boats run most days, but the wind days are the ones operators cancel. A premium small-group catamaran cruise with hotel pick-up is easier to reschedule than a fixed slot.

Swimming at its best

Santorini sea temperature peaks in August at 25.9°C, with July at 24.6°C and September close behind at 25.1°C. That is bath-warm by Aegean standards, and it is the reason August visitors forgive the crowds. The black sand at Perissa and Kamari heats hard by midday, so arrive early for a front-row spot or bring footwear.

Boat days shine in this window despite the wind risk. The caldera water sits calmer than the open east coast, and a half-day exclusive catamaran cruise stops at the warm springs off Palea Kameni, where iron-rich water stains light-coloured swimwear a rusty orange. Wear something you do not mind losing to the volcano.

Why we would book these weeks

May pairs a 20°C (68°F) daytime high with a 19.3°C sea and two rainy days a month. September does better still, at 24°C (75°F) by day, a 25.1°C sea and one rainy day. These are walking months, swimming months and wine months all at once. The vines that make Santorini wine famous are trained in low baskets against the wind, and a terrace tasting at Santo Wines in late September is hard to beat.

October cools to 20.7°C (69°F) by day with a still-warm 23.1°C sea and about four rainy days. It is the last comfortable month for the rim walk, and the crowds thin visibly after the first week. Our Santorini in October page has the detail, including the stepped-down opening hours at Akrotiri.

April is the slow warm-up, at 16.7°C (62°F) by day and a 17.7°C sea, too cool for most swimmers. It suits hikers and sightseers, and the landscape is at its greenest before the summer drought.

What the shoulder season changes practically

Ferry and flight schedules trim back from their summer peak, so check connections before you commit, especially for getting from Athens to Santorini. KTEL buses run a seasonal timetable that shrinks after October, and departure times are not published in fixed form, so check the KTEL PDF on arrival. The full Fira-Oia line costs $2.46 (€2.20) whenever it runs.

Everything major stays open. The cable car between Fira and the Old Port runs from 07:00 with extended evening hours through October, at $11.19 (€10) one way. Museums in Fira, including the Museum of Prehistoric Thera, hold their 08:30-15:30 hours all year.

What the mild numbers hide

Daytime highs of 12.8-17.5°C (55-64°F) sound pleasant until you add the wind funnelling up the caldera. Pack a proper jacket. Rain reaches 55-60 mm in December and January across nine to eleven days, and ferry crossings get rougher, so build slack into any ferry from Mykonos.

The upside is a different island. Imerovigli and Firostefani are walkable in solitude, the blue domes of Oia photograph without queueing, and hotel prices fall hard. Many tavernas and caldera restaurants close for the season, but Fira keeps a year-round core. For the wider trade-offs, see our best time to visit analysis.

What stays open in winter

The big archaeological and museum sites keep reduced hours but stay open. Akrotiri runs 08:30-15:30, closed Tuesdays, at $22.40 (€20) full price. Ancient Thera on Mesa Vouno above Kamari is the exception to plan around, open only Fridays to Sundays in November, by appointment from December to February, and Thursdays to Mondays in March. The Dorian city dates from the 9th century BC.

Boats to the volcano run year-round when the sea allows, though with fewer departures. The three-hour volcano and hot springs cruise format still works in a 14°C noon, and the €5 park fee applies in any month. The cable car cuts to morning and afternoon windows in winter, roughly 07:30-10:30 and 14:30-18:00 in November and March, with a maintenance break in the deep winter months, so check before relying on it.

When the sea is warm enough

The sea tops 22°C from June through November, peaking at 25.9°C in August. That is seven months of genuinely comfortable swimming, which surprises people who assume the Aegean is cold. Even January reads 17.8°C, cool enough that only hardy swimmers bother yet far from icy. Our pick for a pure beach-and-swim trip is early September, when the sea is at 25.1°C and the air has eased to 24°C.

Beach choice matters as much as month. The east coast at Perissa and Kamari takes the meltemi swell in summer, while the south coast at Vlychada and the caldera side stay calmer. If snorkelling is the point, a catamaran day with meal and open bar gets you to the clear water off Red and White beaches that the shore cannot reach.

Red Beach and the closed path

Red Beach below Akrotiri is the most photographed swim spot on the island, and the one with a catch. The land path is closed by the municipality for rockfall danger, and a rockfall after the February 2025 earthquake confirmed the risk. Treat it as reachable only by boat or from the viewpoint above.

Several caldera boats pass it, including the budget classic catamaran cruise from Vlychada and the volcano, hot springs and Thirassia cruise from the port. The water in front of the red and white cliffs is exactly what the boats stop for, so a swim here costs you no extra planning. Our Santorini beaches guide ranks the alternatives.

Build a wind-proof itinerary

Book your boat day for the first calm-looking day of the trip, not the last. If the meltemi cancels it, you still have days to rebook. On windy days swap to land plans that the wind cannot touch, like the roofed galleries at Akrotiri and the Archaeological Museum of Thera, or a wine afternoon in Megalochori and Pyrgos.

Structure ideas by length are in our one day, two day and three day itineraries. The rim walk between Fira and Oia needs a calm, cool window, so it belongs in the morning of a low-wind day in May, June, late September or October. Sunset viewing from the Oia castle area works in any weather, but a still evening transforms it.

Costs shift with the season

High season prices everything up, from hotels to the premium on a sunset cruise. Winter reverses it, and the shoulder months sit in the middle. Two fixed costs are worth knowing regardless of month. Every cruise passenger disembarking at Santorini pays a fee of €20 from June to September, €12 in April, May and October and €4 the rest of the year, charged through the cruise line. And every room booked in April to October carries the climate resilience fee per night, from €2 for simple rooms to €15 for five-star hotels and villas, paid at the property.

Our costs of a Santorini trip page totals a realistic daily budget by season, and the free things to do list covers the days when the weather is perfect and the wallet is not.

The verdict table

Every traveller weighs heat, crowds, price and swimming differently. The table below is our read of the year, month by month, built on the climate figures above and how the island operates. Where we give an opinion it is labelled as ours.

If you can only choose two windows

Book late May or the second half of September and you will get Santorini weather close to its best without the peak-season premium or the meltemi at full strength. Both windows have warm enough seas for daily swims, calm enough mornings for the rim walk, and full schedules for boats and buses.

If your dates are fixed to school holidays in July or August, go anyway, but book boats and the cable car expectations early, do the rim walk at dawn, and use the east coast beaches early or late. If winter is your only window, the trip still works, it just becomes a museums, villages and wine trip rather than a beach one.