Kos in September: the weather and best activities for your holiday

Kos, where turquoise waters meet ancient ruins, is an island that captures the essence of Greek island life. This cycling-friendly destination offers everything from hidden coves to bustling marketplaces, while its rich history is evident in the well-preserved ruins scattered throughout the landscape.

September is arguably the island's most appealing month, combining warm sea temperatures with comfortable daytime heat. The summer crowds have largely departed, leaving beaches pleasantly uncrowded, while all amenities remain open. The evening temperature is perfect for enjoying outdoor tavernas and exploring the charming old town.

The weather of Kos through the year

Weather in Kos follows traditional Mediterranean patterns, characterised by hot, dry summers and mild winters. July and August temperatures frequently reach 33°C, while winter months remain gentle, rarely dropping below 10°C. Spring arrives early with warming temperatures from March, and autumn extends the swimming season well into October.

Kos weather in September

Warm days of 29C (84F) combine with balmy evenings of 19C (66F). The temperature feels pleasantly hot without being stifling, and the sea breeze offers natural cooling. Evening temperatures remain perfect for outdoor dining, while daytime heat makes beach visits especially appealing.

The island basks in 9 hours of daily sunshine, with daylight lasting 12.5 hours. Sunrise occurs around 7:00 AM, with sunset at 7:30 PM. The UV index remains high despite the advancing season. Clear skies dominate, making it ideal for outdoor activities throughout the day.

Rainfall is minimal in September, with typically just 2 wet days and around 10mm of total precipitation. Any rain usually arrives as a brief shower, clearing quickly to return to the standard sunny conditions. Visitors can confidently plan outdoor activities throughout the month.

The Aegean Sea reaches its peak warmth at 24C (75F), following the long summer heating. These ideal swimming conditions make it perfect for extended time in the water. The sea remains consistently warm throughout the month, even during evening swims.

Arguably the finest month to visit Kos, with perfect conditions all round. Warm 29C (84F) days combine with pleasantly balmy evenings and peak sea temperatures of 24C (75F). The summer crowds have departed, but all facilities remain open, creating an ideal atmosphere. While still considered high season, it's less intense than July and August. The weather is perfect for any activity, from extended beach days to cultural exploration, making it ideal for visitors seeking the complete Kos experience.

The Hippocrates Festival, celebrating the island's most famous son, usually takes place in early September. This cultural festival includes traditional music performances and dance events in various locations around Kos Town, particularly near the Ancient Plane Tree where Hippocrates supposedly taught his students.

Clothes to pack for September in Kos

Pack primarily summer clothing as temperatures remain warm at 29C (84F). Bring plenty of lightweight, breathable items like cotton shorts, t-shirts, swimming gear, and sundresses. Evening temperatures are balmy at 19C (66F), so just a light cardigan or long-sleeved shirt should suffice for dining out. Comfortable walking sandals are essential, and don't forget beach shoes for hot sand. Swimming gear will get plenty of use as the sea is at its warmest.

The best months to visit Kos

The sweet spot for visiting Kos falls in September, when temperatures hover around 29C (84F) and the sea reaches a perfect 24C (75F). The summer crowds have dispersed, yet all facilities remain open, creating an ideal balance. The warm days and pleasant evenings of 19C (66F) suit both beach activities and cultural exploration, while hotel rates begin to decrease from peak season prices.

The worst months to visit Kos

Avoid peak summer (July-August) when the combination of intense heat, peak prices, and maximum crowds can diminish the Kos experience. The beaches become crowded, restaurants are fully booked, and the midday heat can be too intense for comfortable sightseeing or activities.

Sights and activities for Kos during September

The Ancient Agora, centrally located in Kos Town, offers an impressive glimpse into the island's Hellenistic and Roman periods. The extensive archaeological site is particularly pleasant to explore during September's moderate temperatures, with the restored columns and mosaics beautifully illuminated during the golden evening hours.

The Castle of Neratzia, a striking 15th-century fortress built by the Knights of St. John, commands attention at the harbour entrance. Its massive walls and twin defensive enclosures are best photographed in September's clear morning light. Visitors can climb the restored sections for panoramic views across to Turkey's coastline.

Asclepieion, the ancient healing temple complex situated in the pine-covered hills 4km southwest of Kos Town, demands unhurried exploration. The three-terraced sanctuary, once a renowned medical school, benefits from September's comfortable temperatures for climbing its impressive restored staircases. The site's connection to Hippocrates makes it especially relevant during the month's cultural festivities.

The mountain village of Zia, nestled in the slopes of Mount Dikeos, offers a quintessential Greek island experience. Time your visit for sunset, when the village's tavernas fill with the aroma of traditional herbs and the views extend across the entire island to neighbouring Kalymnos. The village's position at altitude provides welcome relief from any residual afternoon heat.

Kardamena's thermal springs, located along the southern coast, prove particularly inviting during September when evening temperatures begin to cool. The natural pools, rich in healing minerals, maintain a constant temperature of 50°C year-round, creating an atmospheric steam in the cooler evening air.

Paradise Beach, with its striking dark volcanic sand, offers excellent conditions for windsurfing during September when the meltemi winds moderate to perfect levels for both beginners and intermediate riders. The beach's western position also makes it an ideal spot for watching the sun set over the neighbouring islands.

Other holiday destinations recommendations for September

For September holidays, the Mediterranean region offers exceptional options as summer heat mellows into perfectly warm days. Croatia's Dalmatian Coast, particularly Hvar and Split, provides an enticing blend of historical sites and crystal-clear waters, with temperatures around 25°C and minimal rainfall. The tourist crowds begin to thin while restaurants and facilities remain fully operational.

The Amalfi Coast in Italy shines during September, when the intense summer crowds disperse and temperatures become more comfortable for exploring vertical towns like Positano and Ravello. The sea remains warm enough for swimming, and you'll find it easier to secure restaurant reservations and boat tours.

Portugal's Algarve region enjoys ideal conditions in September, with temperatures around 27°C and virtually guaranteed sunshine. The Atlantic waters are at their warmest after the summer months, and the golden beaches become more peaceful. The evening atmosphere in towns like Lagos and Tavira feels authentically Portuguese as the peak tourist season winds down.

Malta offers an extended summer experience in September, with temperatures around 28°C and exceptionally warm sea temperatures of 25°C. The UNESCO World Heritage site of Valletta becomes more pleasant to explore as the fierce summer heat subsides, and the island's famous beach coves are less crowded.

For something different, the Azores archipelago experiences some of its best weather in September. The islands enjoy stable temperatures around 23°C, perfect for hiking volcanic trails and whale watching. The thermal pools and botanical gardens are particularly enjoyable during this time.

Southern Cyprus provides excellent September conditions, with temperatures around 30°C and warm sea temperatures of 26°C. The wine regions around Limassol celebrate harvest season, while the Troodos Mountains offer cooler temperatures for hiking and exploring traditional villages.

Madeira presents another compelling option, with temperatures steady at 25°C and low rainfall. September brings perfect conditions for levada walking, botanical garden visits, and swimming in the natural volcanic pools. The wine harvest festivals add cultural interest to any visit during this period.

The French Riviera becomes more accessible in September as summer crowds diminish. Nice, Antibes, and the perched villages of the interior benefit from temperatures around 24°C, ideal for combining beach time with cultural exploration. The Mediterranean remains warm enough for comfortable swimming, while the evening light creates perfect conditions for photography.

For those seeking more adventure, Montenegro offers a less discovered alternative. The Bay of Kotor enjoys pleasant temperatures around 25°C, perfect for exploring medieval towns and national parks. The Adriatic Sea remains warm, and the mountain regions provide excellent hiking conditions.