Weather in Mykonos in September

How September compares

September is the 4th warmest month of the year in Mykonos and ranks 106th of 134 destinations we compare for September - see where else is hot in September. Within Greece it is 35th of 44 (Greece in September). Against London's average high of 18.6°C in September, Mykonos is 5.7°C warmer by day and 10.3°C warmer at night.

Daytime and night-time in September

The typical September day in Mykonos peaks at 24.3°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 167 pass 30°C. Nights average 21.5°C; one night in ten drops to 19.3°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest September day here reached 31.3°C (2017-09-18) and the coldest night 16.1°C (2014-09-28).

Rain in September

Dry (3 rainy days or fewer): about 1 days with 1 mm or more, 6 mm in total. Year to year it varies a lot - the wettest September was 2015 with 29 mm, the driest 1991 with 0 mm. Humidity averages 72%.

Sea temperature in September

The sea averages 23.5°C - warm enough to swim (22°c+). Depending on the year it ranges from 22.4°C to 24.5°C. For the warmest sea here, come in August (24.3°C).

Sunshine and daylight

Around 10.7 hours of sunshine a day (estimated from cloud cover), 12.2 hours of daylight: the sun rises about 07:01 and sets about 19:27 local time in mid-September. Average cloud cover is 12%.

Is September a good time to visit Mykonos?

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

Warm days and mild evenings

Mykonos averages 24.3°C by day in September, compared with London's 18.6°C, so the difference should feel noticeable without being overwhelming. Light clothing makes sense during the day, with shade and sun protection sensible around midday. Humidity averages 72%, which can make the warmth feel a little heavier than the temperature alone suggests. Evenings are generally mild enough for sitting outside, though a light layer is useful if you feel the cold. The coldest 10% of nights fall to 19.3°C or lower, so do not assume every evening will feel equally warm. This is a good fit if you prefer manageable warmth to persistent heat.

Good swimming weather, with little rain

The sea averages 23.5°C, making September a reasonable choice if swimming is central to your holiday. Its year-to-year range of 22°C to 24°C stays within the warm-enough-to-swim bracket, though personal comfort varies. Rain is unlikely to dominate your plans: September has about 1 rainy day on average, but that is not a guarantee of a completely dry stay. Sunshine averages about 10.7 hours out of 12.2 hours of daylight, leaving plenty of scope for time outdoors without squeezing everything into midday. Pack swimwear and sun protection as priorities, and keep plans flexible if a shower arrives rather than expecting to spend much of the holiday indoors.