Your December weather guide
MildWeather in Kos in December
Kos in December suits a mild-weather break, not a winter beach holiday. Average daytime highs are around 16°C, nights stay near 13°C, and about 13 days bring rain. That makes it a reasonable choice if you want to spend time outdoors without summer heat and can keep your plans flexible. The catch is the wet weather: pack for showers and cool evenings rather than expecting reliable sunshine or comfortable sea swimming.
Long-term climate averages for Kos Town, not a forecast · 1991-2020
Kos, month by month
Your snapshot
At a glance
The useful details for Kos Town.
- Average daytime high
- 15.6°C
- 9 in 10 days stay below 18°C
- Average night-time low
- 12.9°C
- coldest 10% of nights: 9°C or lower
- Compared with London
- +7.9°C
- London averages 7.7°C in December
- Sea temperature
- 18.9°C
- year to year: 18°C to 20°C
- Sunshine per day (est.)
- 4.9h
- 52% of 9.5 h of daylight
- Rainy days (1 mm+)
- 13
- 181 mm over the month
- Humidity
- 69%
- Days over 25°C
- 0%
- none over 30°C
- Record high 1991-2020
- 20.7°C
- 2010-12-03
- Record low 1991-2020
- 4.5°C
- 1992-12-24
- Flight from London
- ≈ 4 h 6 min
- 2683 km, short-haul (estimate for a direct flight)
Records are observed extremes within 1991-2020, not typical holiday conditions. Warm-day percentages are shares of days, not day counts.
How December compares
December is the 9th warmest month of the year in Kos and ranks 75th of 134 destinations we compare for December - see where else is hot in December. Within Greece it is 14th of 44 (Greece in December). Against London's average high of 7.7°C in December, Kos is 7.9°C warmer by day and 10.2°C warmer at night.
Daytime and night-time in December
The typical December day in Kos peaks at 15.6°C, but that is an average: the warmest 10% of days reach 18.4°C or more. Days over 25°C are rare. Nights average 12.9°C; one night in ten drops to 9.1°C or lower, so pack a layer for evenings - it is genuinely cool after dark. Between 1991 and 2020 the hottest December day here reached 20.7°C (2010-12-03) and the coldest night 4.5°C (1992-12-24).
Rain in December
Wet (more than 8 rainy days): about 13 days with 1 mm or more, 181 mm in total. Year to year it varies a lot - the wettest December was 2012 with 433 mm, the driest 2015 with 2 mm. Humidity averages 69%.
Sea temperature in December
The sea averages 18.9°C - bracing (18-22°c). Depending on the year it ranges from 18.0°C to 19.7°C. For the warmest sea here, come in August (25.2°C).
Sunshine and daylight
Around 4.9 hours of sunshine a day (estimated from cloud cover), 9.5 hours of daylight: the sun rises about 07:17 and sets about 16:55 local time in mid-December. Average cloud cover is 48%.
Is December a good time to visit Kos?
December is not the strongest month here: mild days and frequent rain. The best months for Kos on our scoring are August, July, June; months averaging 25°C or more: Jul, Aug, Sep.
Mild days, but leave room for rain
The daytime temperature is comfortable for walking in layers, with little reason to plan around midday heat. Rain is the bigger constraint: December is wet, so a waterproof jacket and shoes that cope with showers are more useful than a suitcase built around beachwear. There are about 4.9 hours of sunshine within 9.5 hours of daylight, leaving scope for pleasant outdoor spells without making sunshine dependable. Keep outdoor plans flexible rather than committing to a full day outside regardless of the forecast. Evenings need an extra layer, and the coldest nights can fall to 9.1°C or below, so do not treat the mild average as a guarantee.
The sea is bracing, not beach-holiday warm
At an average of 18.9°C, the sea is bracing rather than comfortably warm. A swim may appeal if you already enjoy cooler water, but it should not be the main reason to book December. Bring something warm to put on afterwards, especially when the air feels cool. The wider trade-off is straightforward: Kos offers mild conditions for time outdoors, but neither dependable dry weather nor summer warmth. It suits travellers who are happy to adapt their day to the weather and leave swimming optional. If warm-water swimming and hot afternoons are central to your holiday, December is not a good fit.
A little perspective
Kos through the year
December is highlighted. See how it compares with the rest of the year.
| Month | Day | Night | Sea | Sun/day | Rain mm | Rainy days | Days 25°C+ |
|---|---|---|---|---|---|---|---|
| January | 14.0°C | 11.3°C | 17.5°C | 5.2 | 163 | 12 | 0% |
| February | 14.2°C | 11.2°C | 16.7°C | 5.8 | 127 | 12 | 0% |
| March | 15.4°C | 12.5°C | 16.4°C | 7.0 | 74 | 8 | 0% |
| April | 17.6°C | 14.5°C | 17.0°C | 8.4 | 39 | 6 | 1% |
| May | 21.0°C | 17.8°C | 19.4°C | 10.4 | 16 | 3 | 5% |
| Junebest | 24.8°C | 21.7°C | 22.2°C | 13.3 | 2 | 1 | 41% |
| Julybest | 26.8°C | 23.9°C | 23.8°C | 14.1 | 0 | 0 | 87% |
| Augustbest | 27.4°C | 24.6°C | 25.2°C | 13.2 | 0 | 0 | 94% |
| September | 25.3°C | 22.5°C | 24.5°C | 11.1 | 15 | 2 | 57% |
| October | 22.3°C | 19.5°C | 22.8°C | 8.1 | 60 | 5 | 8% |
| November | 18.8°C | 15.9°C | 20.8°C | 6.0 | 117 | 9 | 0% |
| DecemberSelected | 15.6°C | 12.9°C | 18.9°C | 4.9 | 181 | 13 | 0% |
Day = average daytime high, night = average night-time low, 1991-2020.Sun is hours per day; rainy days count 1 mm or more.
Day, night and sea
Monthly average temperatures, 1991-2020
- Day
- Night
- Sea
Best months here
On warmth, low rainfall and sunshine, start with these.
Keep exploring
Similar in December
Closest matches on daytime temperature, sea temperature and sunshine, in other countries.
A little more detail
Kos in December FAQs
Plain answers, grounded in the averages.
Is Kos hot in December?
Kos is mild in December: the average daytime high is 15.6°C and nights average 12.9°C. Days over 25°C are rare in December.
Can you swim in the sea in Kos in December?
The sea around Kos averages 18.9°C in December, which is bracing - fine for a quick dip, cool for long swims. Between 1991 and 2020 it ranged from 18°C to 20°C depending on the year.
How much does it rain in Kos in December?
Kos sees about 13 rainy days (1 mm or more) and 181 mm of rain in a typical December. The wettest December between 1991 and 2020 was 2012 (433 mm) and the driest was 2015 (2 mm).
How sunny is Kos in December?
Kos gets around 4.9 hours of sunshine a day in December out of 9.5 hours of daylight (estimated from average cloud cover).
How does Kos compare with the UK in December?
Kos is on average 7.9°C warmer than London by day in December (15.6°C against 7.7°C).
What is the hottest December on record in Kos?
Between 1991 and 2020 the hottest December day in Kos reached 20.7°C on 2010-12-03, and the coldest night dropped to 4.5°C on 1992-12-24.
How much warmer is Kos than London in December?
Kos has an average daytime high of 15.6°C, compared with London's 7.7°C. That is a noticeable step up in daytime warmth, but still mild rather than hot. You will want layers and waterproofs, not just summer clothes.
Can I expect hot days in December?
No. Even the warmest 10% of days reach 18.4°C or more, while the share reaching 25°C is 0%. Think comfortable temperatures for walking rather than heat for sunbathing, and do not book on the assumption of a hot spell.
How long is the flight from London?
The flight from London is about 4 h 6 min, making Kos a short-haul option for milder December weather. The decision is less about the flying time than accepting wet days and a bracing sea when you arrive.
About these averages
ERA5-Land climate reanalysis via Open-Meteo (11 km grid) and NOAA Coral Reef Watch 5 km sea temperatures, 1991-2020
Averages computed from daily values at Kos (Kos Town). Sea temperature from the nearest 5 km sea cell, 2.3 km from that point. Sunshine hours are estimated from average cloud cover.Records are the highest and lowest daily values in that 30-year period, not all-time records. These are climate averages, not a forecast for your trip. How we measure holiday weather
- Hot · 25°C+
- Warm · 20°C to below 25°C
- Mild · 15°C to below 20°C
- Cool · below 15°C