The best time to visit Skiathos or Kos largely depends on what kind of experience you’re looking for, but here’s a breakdown to help you choose the ideal time for your trip:

Skiathos

1. Peak Season (June to August)

• Best for: Beach lovers, nightlife enthusiasts, and those who enjoy a lively atmosphere.
• Pros: This is when Skiathos is at its most vibrant. The weather is hot and sunny, perfect for beach activities. All restaurants, bars, and clubs are open, offering plenty of options for dining, entertainment, and nightlife. The island hosts various events, including beach parties and cultural festivals.
• Cons: Crowds are at their peak, especially in popular areas like Skiathos Town and Koukounaries Beach. Prices for accommodation and flights are higher, and it can be challenging to find a secluded spot on the beach.

2. Shoulder Season (May and September)

• Best for: Travelers looking for good weather with fewer crowds.
• Pros: May and September offer pleasant weather, with warm temperatures and plenty of sunshine, but without the intense heat of summer. The island is less crowded, making it easier to explore popular spots and enjoy the beaches. Prices for accommodation are more reasonable, and the island still has a lively, but more relaxed, vibe.
• Cons: While most businesses are open, some seasonal venues may begin to close in late September. The sea is warm enough for swimming, but it might be cooler than during peak summer.

3. Off-Season (October to April)

• Best for: Those seeking a quiet retreat and budget travelers.
• Pros: The island is very quiet, offering a peaceful atmosphere perfect for relaxation. Prices for accommodation drop significantly, making it an excellent time for budget-conscious travelers. The weather in October can still be mild, and it’s a good time for hiking and exploring the natural beauty of the island without the crowds.
• Cons: Many tourist facilities, including restaurants, bars, and shops, close down for the season. The weather can be unpredictable, with cooler temperatures and occasional rain. The island has very limited nightlife during this period.

Kos

1. Peak Season (June to August)

• Best for: Beach holidays, nightlife, and outdoor activities.
• Pros: Kos experiences hot, sunny weather, ideal for beachgoers. The island is bustling with tourists, and all facilities, from water sports to nightlife venues, are in full swing. Kos Town and Kardamena are particularly lively, with plenty of events and activities.
• Cons: The island is crowded, especially in popular areas. Prices for accommodation and flights are at their highest, and it can be more challenging to enjoy the island’s historical sites without the crowds.

2. Shoulder Season (April to May and September to October)

• Best for: Exploring the island, enjoying the beaches, and experiencing local culture.
• Pros: The weather during these months is still warm and pleasant, perfect for sightseeing and outdoor activities. The island is less crowded, allowing for a more relaxed experience. Spring is especially beautiful, with wildflowers blooming across the island, and the sea is warm enough for swimming from late May and throughout September.
• Cons: While the weather is generally good, it can be a bit cooler in early spring and late fall. Some seasonal businesses may start to close in October.

3. Off-Season (November to March)

• Best for: Cultural and historical exploration, and a quiet retreat.
• Pros: Kos is very quiet during the off-season, making it ideal for those who want to experience the island without the tourist crowds. It’s a good time to explore the historical sites and local villages at a leisurely pace. Prices for accommodation are very low, making it a budget-friendly time to visit.
• Cons: Many tourist facilities, including beach bars, clubs, and some restaurants, close down for the winter. The weather is cooler, and there can be rain, making it less suitable for beach activities.

Conclusion

• Skiathos is best visited during the shoulder season (May and September) if you want good weather, fewer crowds, and more affordable prices. If you enjoy a lively atmosphere and don’t mind the crowds, then June to August is perfect.
• Kos also shines during the shoulder season (April to May and September to October) when the weather is pleasant and the island is less crowded. The peak season (June to August) is ideal if you’re looking for vibrant nightlife and hot beach days.

Choose the timing that aligns with your travel preferences, and you’ll have an incredible experience on either island!