Weather in Skiathos in September

How September compares

September is the 3rd warmest month of the year in Skiathos and ranks 114th of 134 destinations we compare for September - see where else is hot in September. Within Greece it is 40th of 44 (Greece in September). Against London's average high of 18.6°C in September, Skiathos is 5.2°C warmer by day and 10.6°C warmer at night.

Daytime and night-time in September

The typical September day in Skiathos peaks at 23.8°C, but that is an average: the warmest 10% of days reach 26.3°C or more. Roughly 1 in 3 days top 25°C and 1 in 500 pass 30°C. Nights average 21.8°C; one night in ten drops to 19.2°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest September day here reached 30.3°C (2000-09-01) and the coldest night 15.5°C (2008-09-29).

Rain in September

Some rain (4-8 rainy days): about 5 days with 1 mm or more, 51 mm in total. Year to year it varies a lot - the wettest September was 2009 with 176 mm, the driest 1994 with 0 mm. Humidity averages 70%.

Sea temperature in September

The sea averages 24.4°C - warm enough to swim (22°c+). Depending on the year it ranges from 23.5°C to 25.4°C. For the warmest sea here, come in August (26.3°C).

Sunshine and daylight

Around 9.0 hours of sunshine a day (estimated from cloud cover), 12.2 hours of daylight: the sun rises about 07:07 and sets about 19:35 local time in mid-September. Average cloud cover is 26%.

Is September a good time to visit Skiathos?

It is a reasonable choice: warm days. The best months for Skiathos on our scoring are July, August, June; months averaging 25°C or more: Jul, Aug.

Warm enough for light clothes, without reliable high heat

The average daytime high of 23.8°C suits travellers who prefer warmth to very hot afternoons. Days reach 25°C around 29% of the time, so do not choose September expecting consistently hot weather. Humidity averages 70%, which can make the warmth feel closer, particularly when you are active; shade and a pause at midday can still be welcome. Nights average 21.8°C, so evening meals outdoors should generally feel mild. However, the coldest nights can fall to 19.2°C or lower. A light jumper or cardigan is a sensible addition, rather than relying entirely on the clothes you wear by the water.

Good swimming conditions, with room for rain

The sea is a strong reason to go in September: at an average 24.4°C, it is warm enough for swimming rather than just a quick, bracing dip. Sunshine averages about 9.0 hours out of 12.2 hours of daylight, leaving a useful window for spending time outdoors. The catch is that September is not reliably rain-free. About 5 days have measurable rain, so leave some flexibility rather than making every day depend on clear skies. That figure does not mean each wet day is a washout, but neither does it tell you when rain will arrive. Bring a light waterproof alongside swimwear and sun protection.