Weather in Kos in January

How January compares

January is the 12th warmest month of the year in Kos and ranks 79th of 134 destinations we compare for January - see where else is hot in January. Within Greece it is 16th of 44 (Greece in January). Against London's average high of 7.4°C in January, Kos is 6.6°C warmer by day and 9.1°C warmer at night.

Daytime and night-time in January

The typical January day in Kos peaks at 14.0°C, but that is an average: the warmest 10% of days reach 16.7°C or more. Days over 25°C are rare. Nights average 11.3°C; one night in ten drops to 7.4°C or lower, so pack a layer for evenings - it is genuinely cool after dark. Between 1991 and 2020 the hottest January day here reached 19.4°C (2010-01-01) and the coldest night 1.9°C (2015-01-08).

Rain in January

Wet (more than 8 rainy days): about 12 days with 1 mm or more, 163 mm in total. Year to year it varies a lot - the wettest January was 2004 with 395 mm, the driest 1992 with 9 mm. Humidity averages 68%.

Sea temperature in January

The sea averages 17.5°C - too cold for most (under 18°c). Depending on the year it ranges from 16.7°C to 18.3°C. For the warmest sea here, come in August (25.2°C).

Sunshine and daylight

Around 5.2 hours of sunshine a day (estimated from cloud cover), 9.7 hours of daylight: the sun rises about 07:23 and sets about 17:17 local time in mid-January. Average cloud cover is 47%.

Is January a good time to visit Kos?

January is not the strongest month here: cool 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.

Milder than London, but still jacket weather

The daytime average is useful for walking outdoors without summer heat, but it is not a promise of shirtsleeve weather. Warmer days can reach around 17°C, while the coldest nights drop to around 7°C or below. Bring layers you can adjust, a jacket for evenings and closed shoes rather than relying on sandals. Compared with London's January high of 7.4°C, Kos is noticeably milder at 14°C, though the difference is better thought of as less cold than genuinely warm. It suits travellers who are comfortable spending time outside in cool conditions, rather than those seeking heat.

Leave room for rain in your plans

January is wet, with about 12 rainy days, so a rigid outdoor itinerary is a poor fit. A waterproof jacket and shoes that can handle wet ground are more useful than a suitcase built around beachwear. There are about 5.2 hours of sunshine within 9.7 hours of daylight, giving you scope for time outside without promising a clear day. Make use of brighter spells and keep an indoor alternative for wetter weather. The practical trade-off is flexibility: January can work if you do not mind changing plans, but it is less suitable if daily sunshine is central to the trip.

Treat the sea as cold, not swimming weather

The sea averages 17.5°C, which is cold rather than comfortably swimmable. If relaxed swimming is the main reason for going, January is a poor match; even the milder afternoons do not turn it into a summer-style beach break. You might still enjoy being outdoors by the water, but plan around layers and dry clothes rather than long spells in a swimsuit. June, July and August are the better-rated months overall, so consider those instead if your dates are flexible. January makes more sense when you are choosing a cool island stay and do not need the sea to be inviting.