Weather in Marseille in September

Prime time. September is about as good as Marseille gets. Highs average 27.7 °C, lows 16.1 °C, and rain falls on 6 days — nothing in the month is working against you.

September ranks 3 of 12 in Marseille. Only May scores clearly higher, and the difference is small enough to be settled by price rather than weather.

Rain falls on only 6 days, so an itinerary with no wet-weather fallback is a reasonable risk. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: 8 days top 30 °C — hot spells arrive, but they break. Across the twenty years measured, the hottest September day reached 35.7 °C and the coldest night fell to 7.6 °C, and the wettest single day dropped 38 mm — roughly 76% of the month's rain in one day.

September is moderately variable: 4 mm in the driest year against 125 mm in the wettest, around an average of 50 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 10.3 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 63%.

How September sits in the year

The month is on the way down: 4.9 °C cooler than August, with October dropping another 5.1 °C. The first week and the last are not the same trip.

Daylight in September

12.6 hours of daylight, losing 1.5 hours across the month. That is between Marseille's extremes of 15.4 and 9 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 20.7 °C in September — swimmable, but it takes a moment to commit. This is the warmest the water gets all year.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead. If the dates are flexible, March is the trade worth considering — 10 points weaker on weather, and materially quieter.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

September in Marseille versus nearby

If Marseille is one option among several, the nearby comparison is worth making. Montpellier is close enough to be a coin toss — 2.2 °C cooler, 1 day more rain. Nice is close enough to be a coin toss — 4.7 °C cooler, 1 day more rain.

So: September is effectively as good as it gets here — 3 points behind May, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Marseille

See all twelve months in Marseille, or where else to go in September.