Best Time to Visit Sithonia: Month-by-Month Weather and Crowds

The best time to go to Sithonia depends on what you want from the sea. If you want warm water and long beach days, think June to September. If you want the same coast with more room and cooler air, the edges of that window do the job nicely. If you want hiking, quiet villages and no swimming at all, spring and autumn have their own case.

Below are the figures behind that answer: air and rain from a weather station on the peninsula, sea temperatures for Sarti, and sunshine from the nearest station with long-term records, followed by our pick of the months.

The short answer

• Best balance of warm sea and fewer people: June and September.
• Hottest and driest: July and August, when the mean daily maximum is about 32 C and August sees only 11 mm of rain on average.
• Wettest and coolest: November to January, with December the wettest month.
• Swimming season: roughly June to September for most people, with May and October possible if you are happy with cooler water.

Climate at a glance

A few notes on the figures before you read the table.

The air and rain figures come from the Neos Marmaras weather station (National Observatory of Athens, February 2014 to November 2025). Neos Marmaras is on the west coast of Sithonia and Sarti is on the east coast, so expect small differences. The sunshine and rainy-day columns come from Thessaloniki Airport on the mainland, about 130 km from Sarti by road (1991-2020 normals), so treat them as a regional guide rather than a Sithonia measurement.

Sea temperatures are for Sarti, averaged from daily satellite sea-surface readings. They can vary slightly with time of day, wind direction and river runoff.

*Thessaloniki Airport figures, as a regional guide.

Across the year the Neos Marmaras station shows a mean maximum of 21.8 C and 432.2 mm of rain. The record high is 41.6 C (August) and the record low -4.2 C (in midwinter). Neos Marmaras has a hot semi-arid climate with strong Mediterranean influence, and most of Chalkidiki is Mediterranean, with cool, wet winters and hot, relatively dry summers.

June, July, August and September in detail

June

Sea water averages 23.0 C, with a range from 20.6 to 25.4 C across the satellite readings. The air is warm, with a mean maximum of 29.4 C, and days often reach about 28-32 C. June has fewer visitors than the peak, which is why it is one of our two favourite months.

July and August

These are the hot, dry, bright months. The sea averages 26.0 C in July and 26.3 C in August, which makes August the warmest month for swimming. July is the sunniest month in the Thessaloniki table (325.7 hours), and August has the least rain of the year at Neos Marmaras. They are also the busiest months, and tourism and traffic rise significantly in summer, particularly from South-eastern Europe.

If you travel then, take sun protection seriously, and our sea safety guide covers sun, urchins and jellyfish. For the village in peak season, see Sarti in July and August.

September

Sea water is still warm, at 24.3 C on average, and the air is a comfortable 27.9 C at the daily maximum, often about 27-29 C with nights around 17 C. Accommodation is still almost fully booked until about 10 September, rental prices are lower than in July and August, and beaches are less crowded once school starts. The first half of the month is usually dry. For many visitors, September is the sweet spot; see Sarti in September and October for more.

Shoulder season: April, May and October

April and May

In April the sea is about 14.2 C and the air maximum is 19.5 C. That is not swimming weather for most people, but it is good for walking. By May the air reaches 24.3 C, though the sea averages only 17.9 C, which at 18-20 C feels fresh but pleasant. May is quiet. For a village-level view of the season, see Sarti in spring.

For places to aim for once the weather turns, our guide to Vourvourou and Diaporos Island is one starting point, and our complete Sithonia guide covers the peninsula as a whole.

Pack warm layers for the evenings in May, June and October. Our guide on what to pack for a beach holiday in Sithonia has a fuller list.

October

The air maximum is 22.4 C and the sea is 20.6 C on average, so swimming is possible early in the month. The weather is variable, and October is wetter than the summer months, at 34.5 mm. Some shops and restaurants close and accommodation choice is limited.

Winter: what stays open

From November the sea cools to 17.1 C, and by January to March it sits between 13.4 and 14.2 C. December is the wettest month, at 74.1 mm, and January's mean maximum is only 12.3 C.

Winter is quiet. Many places close their doors after September, but some restaurants stay open all year in Sarti, Porto Koufo, Sykia, Nikiti, Neos Marmaras and Ormos Panagias, though some have limited hours or open only at weekends. Phone before you make the trip, and check each hotel, beach bar or boat operator you are relying on, since each sets its own season.

Neos Marmaras is one of the places with year-round restaurants, and our Neos Marmaras guide has more on the town.

The meltemi: wind in summer

The Etesian winds, known in Greece as the meltemi (μελτέμι), blow periodically from about mid-May to mid-September. In the northern Aegean they are northeasterly to northerly and can reach Beaufort 7-8. They are usually strongest in the afternoon and often ease at night, and some spells last for days. They arrive in clear weather and temper the summer heat.

July and August are the strongest and most persistent months, with typical speeds of 11-21 knots in early afternoon and surges to 17-33 knots or higher.

How much a beach feels the wind depends on which way it faces and on the day's wind direction. On a windy day, ask us at reception where the sheltered water is; our Sarti beach guide lists sheltered alternatives for the days when the sea is rough, and our guide to beaches for windy days looks at the wider region.

Crowds and closing times

Accommodation is typically fully booked from about 20 June to 10 September, so book early for July and August, and expect more traffic.

Holidays also matter. Orthodox Easter is a Sunday in April or early May (check the official calendar for your year), and Easter week is a domestic travel peak in Greece. 15 August is a fixed national holiday and falls in the busiest stretch of summer, so book early if your dates include it.

Month picker by traveller type

• Families with small children: June to September, for warm water. Mid-June and the first half of September are quieter than the peak.
• Couples seeking calm and warm sea: June or September.
• Hikers and walkers: April, May and October, when the air is mild. Do not count on swimming.
• Sun-chasers: July and August, with the sunniest, driest conditions.
• Winter visitors: expect cool, wet weather and many closed places, but a few year-round restaurants.

Practical info

• Getting here: Sarti to Thessaloniki Airport is about 130 km, around 125 minutes in free-flowing traffic.
• Sea temperatures: from the Sarti satellite table above. For swimming, 23 C and over is reached from June to September.
• Packing: warm layers for May, June and October evenings; sun protection in July and August.
• Staying: if you would like a base in Sarti, Sarti Thea Boutique Rooms sits above Sarti harbour in Achlada, with a view over the whole bay and free parking on site; see our rooms.

Good to know

• Sunshine figures in the table are for Thessaloniki, so Sithonia may differ slightly.
• Air temperature and rainfall are from Neos Marmaras, on the west coast; Sarti, on the east coast, can differ a little.
• Sea temperatures are for Sarti; west-coast water may differ a little on a given day.
• Hotels, beach bars and boat operators each set their own opening and closing dates.
• Days are longest around June and shortest in December, so plan winter outings for the middle of the day.

Our pick, June and September for most travellers, comes from the averages above.