Kos, a sun-drenched island in the southeastern Aegean Sea, enjoys a Mediterranean climate with hot, dry summers and mild, rainy winters. The island boasts long hours of sunshine, warm sea temperatures, and cooling breezes. With distinct seasons and a long beach-friendly period, Kos is a favourite for beachgoers, history buffs, and outdoor adventurers.
The best times to travel section shows how the months compare for a visit, so you can find the time of year that fits what you want to do.
Background colours of the months:
The colour shows the typical temperature: yellow (hot), green (mild) and blue (cold). How strong the colour is shows the travel season: full colour means high season, soft colour means shoulder season and soft-striped means off season.
Weather symbols:
Each month has one symbol showing what the weather is typically like, such as hot and sunny, freezing or a rainy or snowy season. Use them to quickly spot months that match the weather you want, or to avoid the ones that don't.
Crowdedness:
The people icon shows how busy the place usually is. The more people, the more crowded it gets.
Additional notes:
The grey info boxes point out special things worth knowing, like recurring weather issues or seasonal events.
Kos features a classic Mediterranean climate, with four distinct seasons offering diverse experiences. Summers (June–September) are hot, dry, and sunny, with average highs of 30–33°C and lows of 19–23°C. July and August are the hottest months, often reaching 35°C, but the Meltemi wind brings cooling breezes. Rain is almost nonexistent in summer, with just 1–3 mm monthly, and the island enjoys up to 12–14 hours of sunshine per day. The sea is warmest from July to September, reaching 24–25°C, ideal for swimming and water sports. Humidity is moderate, and evenings are pleasantly cooler, especially in early summer.
Winters (December–February) are mild and wetter, with highs of 13–16°C and lows of 8–10°C. Rainfall is highest in January (up to 170 mm over 12 days), but sunny intervals are frequent. Snow is rare at sea level, though a dusting is possible during cold snaps. Spring (March–May) and autumn (September–November) are transitional, with pleasant temperatures (17–26°C), moderate rainfall, and blooming or colourful landscapes. These seasons are perfect for sightseeing, hiking, and exploring ancient ruins, with fewer crowds and comfortable weather. Annual precipitation averages 700–800 mm, and Kos enjoys nearly 2,900–3,000 hours of sunshine per year. Winds are generally moderate, with the Meltemi strongest from May to September, especially in the afternoons.
| Average climate data for Kos, Greece | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Average maximum temperature (°C) | 14 | 14 | 16 | 18 | 22 | 25 | 28 | 28 | 26 | 22 | 19 | 15 | 28 |
| Average minimum temperature (°C) | 11 | 12 | 13 | 15 | 18 | 22 | 24 | 25 | 23 | 20 | 17 | 13 | 11 |
| Average precipitation (mm) | 81 | 40 | 32 | 18 | 11 | 5 | 1 | 1 | 8 | 27 | 50 | 79 | 352 |
| Average rainfall days (days) | 14 | 13 | 10 | 8 | 7 | 3 | 1 | 0 | 3 | 7 | 9 | 13 | 87 |
| Average relative humidity (%) | 69 | 71 | 69 | 71 | 71 | 68 | 64 | 66 | 66 | 64 | 67 | 68 | 68 |
| Average wind speed (km/h) | 24 | 23 | 21 | 18 | 14 | 16 | 20 | 18 | 18 | 17 | 19 | 22 | 19 |
| Average water temperature (°C) | 18 | 17 | 17 | 17 | 19 | 23 | 24 | 25 | 25 | 23 | 20 | 19 | 21 |
| Average daily daylight hours (h) | 10 | 10 | 12 | 13 | 14 | 14 | 14 | 13 | 12 | 11 | 10 | 9 | 12 |
| Average daily sunshine hours (h) | 7 | 8 | 8 | 9 | 10 | 12 | 10 | 10 | 9 | 9 | 7 | 6 | 9 |
| Average cloud coverage (%) | 37 | 36 | 28 | 22 | 15 | 8 | 3 | 4 | 6 | 15 | 21 | 32 | 19 |
| Average UV index | 4 | 4 | 5 | 5 | 6 | 6 | 7 | 7 | 6 | 5 | 5 | 4 | 5 |
The best time to visit Kos is from late May to early October, when temperatures are warmest (24–33°C), rainfall is minimal, and the sea is perfect for swimming. June and September are especially ideal for enjoying sunny weather, lively beaches, and outdoor activities without the peak summer crowds.
The least favourable time to visit Kos is from December to February, when rainfall is highest, days are shorter, and cooler temperatures may limit beach activities. While winters are mild compared to much of Europe, frequent rain and occasional strong winds can disrupt outdoor plans, though the island remains pleasant for cultural visits.
Kos has a Mediterranean climate with hot, dry summers and mild, rainy winters. Summers are sunny and perfect for beaches, while winters are cooler with more rain. Spring and autumn are mild and ideal for outdoor activities.
The best time to visit Kos is from late May to early October, when the weather is warm, rainfall is low, and the sea is ideal for swimming. June and September offer great weather with fewer crowds.
Rain is most frequent in winter, especially in January, which is the wettest month. Summers are very dry, with almost no rain from June to August. Annual rainfall averages 700–800 mm, mainly in the cooler months.
Summer highs in Kos typically reach 30–33°C, with July and August being the hottest months. Heatwaves can push temperatures above 35°C, but the Meltemi wind helps keep afternoons comfortable.
Yes, the Aegean Sea is warmest from July to September, reaching 24–25°C. Swimming is comfortable from June to October, though the water is cooler in spring and late autumn.
In summer, bring light, breathable clothing, swimwear, sun protection, and a hat. For spring and autumn, pack layers and a light jacket. Winters require a jumper and rain gear for cooler, wetter days.
Snow is extremely rare in Kos due to its mild coastal climate. When it does occur, it melts quickly. Most winter precipitation falls as rain, and the island remains pleasant for exploring year-round.
The warmest month, with the highest average maximum temperature, is August (28.4 °C). The month with the lowest average maximum temperature is January (13.9 °C). Overall, the average maximum temperature over the whole year is 20.7 °C.
The month with the highest average minimum temperature is August (25.1 °C). The coldest month, with the lowest average minimum temperature, is January (11.2 °C). Overall, the average minimum temperature over the whole year is 17.9 °C.
The month with the highest average water temperature is August (25.3 °C). The month with the lowest average water temperature is March (17 °C). Overall, the average water temperature over the whole year is 20.6 °C.
The wettest month, with the highest amount of precipitation, is January (80.5 mm). The driest month, with the least amount of precipitation, is August (1 mm). Over the whole year there are 351.9 mm of rainfall on average.
The month with the most days of rain is January (13.6 days). The month with the fewest days of rain is August (0.4 days). Over the whole year there are 87.4 days of rain on average.
The month with the highest average relative humidity is April (71 %). The month with the lowest average relative humidity is October (63.8 %). The overall average relative humidity over the whole year is 67.6 %.
The windiest month, with the highest average wind speed, is January (23.9 km/h). The calmest month, with the lowest average wind speed, is May (14.4 km/h). The overall average wind speed over the whole year is 19 km/h.
The month with the cloudiest skies, so the highest cloud coverage, is January (36.8 %). The month with the clearest skies, so the lowest cloud coverage, is July (2.7 %). Over the whole year there is an average cloud coverage of 18.9 %.
The month with the longest days, so the most daylight, is June (Average daylight: 14.1 h). The month with the shortest days, so the least daylight, is December (Average daylight: 9.1 h). Over the whole year there are 11.9 h of daylight per day on average.
The month with the most sunshine per day is June (Average sunshine: 12.1 h). The month with the least sunshine per day is December (Average sunshine: 6.1 h). Over the whole year there are 8.8 h of sunlight per day on average.
The months with the highest average UV index are July and August (UV index: 7). The months with the lowest average UV index are January, February and December (UV index: 4). Over the whole year the average UV index is 5.3.
