Weather in Santorini in September

How September compares

September is the 3rd warmest month of the year in Santorini and ranks 115th of 134 destinations we compare for September - see where else is hot in September. Within Greece it is 43rd of 44 (Greece in September). Against London's average high of 18.6°C in September, Santorini is 5.1°C warmer by day and 9.4°C warmer at night.

Daytime and night-time in September

The typical September day in Santorini peaks at 23.7°C, but that is an average: the warmest 10% of days reach 25.7°C or more. Roughly 1 in 5 days top 25°C. Nights average 20.6°C; one night in ten drops to 18.7°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest September day here reached 29.8°C (2020-09-02) and the coldest night 15.5°C (2014-09-27).

Rain in September

Dry (3 rainy days or fewer): about 1 days with 1 mm or more, 5 mm in total. Year to year it varies a lot - the wettest September was 2009 with 24 mm, the driest 1991 with 0 mm. Humidity averages 71%.

Sea temperature in September

The sea averages 24.0°C - warm enough to swim (22°c+). Depending on the year it ranges from 22.9°C to 25.0°C. For the warmest sea here, come in August (24.6°C).

Sunshine and daylight

Around 11.0 hours of sunshine a day (estimated from cloud cover), 12.2 hours of daylight: the sun rises about 07:01 and sets about 19:26 local time in mid-September. Average cloud cover is 10%.

Is September a good time to visit Santorini?

Yes - it is one of the better months: warm days, little rain and long sunny days. The best months for Santorini on our scoring are July, August, September; months averaging 25°C or more: Jul, Aug.

Warm days without the strongest heat

Pack mainly light clothes, but leave room for a light layer rather than assuming every evening will feel hot. Average night lows are 20.6°C, while the coldest 10% of nights fall to 18.7°C or below. During the day, temperatures reach 25°C on 21% of days, so extra warmth is possible but not something to build the holiday around. September suits travellers who want to spend time outdoors without planning everything around fierce afternoon heat. Humidity averages 71%, which can make the warmth feel more noticeable. Keep water and sun protection handy, and use shade at midday if you start feeling uncomfortable.

Good swimming conditions and little rain

The sea is a strong reason to choose September: at an average of 24°C, it is warm enough for swimming rather than just a quick dip. Its year-to-year range of 23°C to 25°C also points to generally comfortable water, though personal tolerance varies. Rain is unlikely to dominate your plans, with about 1 rainy day during the month, but dry averages are not a guarantee for your stay. Sunshine fills much of the daylight, leaving plenty of scope to swim or spend time outside without squeezing everything into a short afternoon. Prioritise swimwear and sun protection over bulky wet-weather clothing.