Else Beekman
The Mediterranean Sea is currently unusually warm. With temperatures reaching nearly 28 degrees Celsius, meteorologists fear an increased risk of heavy rainfall and flooding in autumn. The record heat in June fuels these concerns, though it remains unpredictable how the season will unfold.
According to Spain’s meteorological agency Aemet, June 2025 was the warmest June since records began. The average temperature in the Valencia region reached 23.6 degrees, 3.5 degrees above the 1991–2020 average.
Some locations saw even higher increases. In Morella, Castellón province, June was 4.6 degrees warmer than normal. Vilafranca also recorded its warmest June since 1957.
These high land temperatures are accompanied by an exceptionally warm sea. On 25 June, Aemet measured sea temperatures in the western Mediterranean that were 3.8 degrees above average—similar to what is usually only seen in August.
Risk of intense autumn rains
The unusually warm Mediterranean is worrying meteorologists, according to newspaper Las Provincias. Warm seawater releases energy and moisture into the atmosphere, increasing the chance of so-called danas: powerful, stationary storms that can bring huge amounts of rain in a short time.
Still, Aemet stresses that warm water alone does not cause such severe weather. Several atmospheric conditions must combine. A notable example was in October 2024, when warm air from the east collided with cold air from the north, triggering a major storm over Valencia.
Preparedness remains key
While it is not certain if this autumn will be equally extreme, experts urge caution. Municipalities and residents in vulnerable areas can already prepare by clearing drains and checking flood defences.
Aemet continues to closely monitor sea temperatures, which are expected to rise further as summer progresses.
Anyone visiting the coast of Valencia or other parts of the Mediterranean this summer will likely notice the unusually warm sea. According to local media, the water feels almost lukewarm for this time of year.