French Riviera

The sea in French Riviera peaks in August, when the water averages around 24°C.

The main swimming season runs from June – September, when surface temperatures stay comfortable for extended sessions.

On average, 4 months a year sit above 20°C — the threshold most swimmers describe as pleasant without a wetsuit.

Shoulder months like May and October are noticeably cooler but often quieter, with fewer crowds and steadier weather.

Outside peak season the water drops toward 15°C, so a 3/2mm shorty or full wetsuit makes long swims much more comfortable.

The coldest month is typically January at around 13°C, when cold-water swimmers dominate the coast.

Long-term climatology for French Riviera shows an annual mean sea temperature of 17°C, ranging from 13°C in winter to 24°C at the summer peak.

The seasonal swing is roughly 11°C between the coldest and warmest month — a useful yardstick when comparing years or checking whether the current sea is running above or below average.

Recent decades have trended slightly warmer at French Riviera, in line with regional sea-surface temperature records for the wider basin.

Monthly averages below are drawn from multi-decadal climatology and are updated as new observations arrive.