Ibiza and Formentera are under an orange weather alert as a potentially intense storm system approaches the Balearic Islands, bringing the risk of torrential rain, thunderstorms, hail and very strong wind gusts on Wednesday, September 9.

The Balearic Government's Technical Advisory Committee for the Meteobal emergency plan met urgently on Tuesday to assess the developing situation and activated orange-level alerts across the archipelago for heavy rain and thunderstorms.

For Ibiza and Formentera, the most significant period is expected between 10:00 and 21:00 on Wednesday, when the weather could become particularly unsettled.

Up to 40 Litres of Rain in One Hour

The main concern is the potential intensity of the rainfall.

AEMET forecasts indicate that Ibiza and Formentera could receive accumulations of up to 40 litres per square metre in just one hour during the most active part of the storm.

The probability of reaching the warning threshold is estimated at between 40% and 70%.

Rainfall of this intensity can cause rapid flooding in low-lying areas, roads, drainage channels and other locations where water accumulates quickly.

Residents and visitors are therefore being advised to take precautions before the most intense conditions arrive.

Thunderstorms Could Bring Hail and Gusts Over 90 km/h

Thunderstorms are expected to be another major feature of Wednesday's weather.

Some storms could produce hail and very strong wind gusts, with AEMET warning that gusts associated with the storms could exceed 90 km/h.

These conditions can create risks from falling branches, loose objects, damaged structures and difficult driving conditions.

Storms may also develop unevenly across the islands, meaning conditions could change quickly between different parts of Ibiza and Formentera.

Orange Alert Runs From Morning Into the Evening

The orange warning for Ibiza and Formentera is scheduled to run from 10:00 until 21:00 on Wednesday.

Outside that period, the warning level drops to yellow.

From 21:00 until midnight, the risk associated with rain and thunderstorms remains at a lower level, with rainfall totals of up to around 30 litres per square metre in one hour.

The situation is expected to gradually improve after the main storm period, although some unsettled conditions may continue overnight.

Strong Winds and Rough Seas

The adverse weather will not be limited to land.

A separate coastal warning is in place for Ibiza and Formentera from 08:00 to 23:59 on Wednesday.

Winds from the north and northeast are expected to reach between 40 and 60 km/h, equivalent to force 6 to 7.

Waves of approximately two to four metres are expected in surrounding waters.

AEMET's marine forecast also warns of heavy showers and thunderstorms, with conditions becoming rough to very rough.

Thursday Should Bring Gradual Improvement

The weather is expected to improve progressively on Thursday, September 10.

However, a yellow alert remains in place during the early hours, from midnight until 07:59, with possible rainfall of up to 30 litres per square metre in one hour and the possibility of further thunderstorms.

The coastal warning is expected to continue until 11:59 on Thursday, with winds of around 40 to 50 km/h and waves between two and three metres.

By later Thursday, the overall situation should become more stable.

A Major Drop in Temperatures

The storm system will also bring a significant change in temperatures.

After Ibiza and Formentera experienced temperatures in the mid-30s at the beginning of the week, the arrival of cooler air is expected to produce a drop of around 10°C.

The change will therefore be felt not only through rain and storms but also through substantially cooler conditions.

It marks a sharp transition from the prolonged late-summer warmth to a more unsettled early-autumn weather pattern.

Emergency Authorities Urge Caution

The Balearic Government's Directorate General of Emergencies is asking the public to remain particularly cautious during the storm episode.

Residents are advised to secure doors and windows, remove or secure objects from balconies and terraces and take measures to prevent water from entering homes.

People should also avoid unnecessary journeys during periods of particularly heavy rain and thunderstorms.

The authorities are urging everyone to monitor official weather updates because the intensity and location of individual storms can change rapidly.

Avoid Flood-Prone Areas

People are being warned not to enter torrents, drainage channels or other areas vulnerable to sudden flooding.

Drivers should never attempt to cross a road covered by floodwater, even if the water appears shallow.

Floodwater can conceal holes, obstacles and damaged road surfaces, while moving water can quickly become powerful enough to move vehicles.

Pedestrians should also avoid walking through flooded areas.

Coastal Areas Could Become Dangerous

The combination of strong winds, large waves and thunderstorms makes exposed coastal areas particularly hazardous.

Emergency authorities are advising people to stay away from promenades, breakwaters, cliffs and other places where waves can suddenly reach higher than expected.

Water sports should be avoided while the coastal warning remains active.

Boat owners are also advised to make sure vessels and moorings are properly secured before the strongest winds arrive.

Why the Change Is Happening So Quickly

The incoming weather represents a sharp contrast with the conditions experienced only a few days earlier.

On September 7, Formentera recorded a maximum temperature of 36.1°C, according to AEMET observations.

By Wednesday, the islands are instead dealing with the possibility of intense thunderstorms and a substantial temperature drop.

September is a transition month in the Balearics, and conditions can change rapidly as more unstable weather systems begin affecting the western Mediterranean.

The Mediterranean Is Still Exceptionally Warm

The storm arrives against a background of unusually warm Mediterranean waters.

AEMET recently recorded a basin-wide Mediterranean sea surface temperature of 28.54°C on August 13, the highest value in its comparable records dating back to at least 1940.

Warm seas do not automatically produce severe storms, but unusually high water temperatures can provide additional heat and moisture to the atmosphere when an unstable weather system passes over the region.

That makes the current weather episode particularly notable after an exceptionally warm summer.

What Visitors to Ibiza and Formentera Should Know

For tourists on the islands, Wednesday is likely to be the most challenging day of the week.

Boat excursions, beach plans, hiking and other outdoor activities could all be affected by the combination of thunderstorms, rain, hail and strong winds.

Even if conditions appear calm early in the day, the orange warning covers a long period from late morning into the evening.

Visitors should therefore check the latest forecasts before heading out and follow any instructions issued by local emergency services.

A Short but Potentially Intense Storm Episode

According to AEMET's forecasts, the episode is not expected to last for many days.

The main concern is its potential intensity rather than its duration.

Wednesday is expected to be the most adverse day, while conditions should gradually improve on Thursday.

The coastal impact may last somewhat longer than the heaviest rainfall, with rough seas continuing into Thursday morning.

Ibiza and Formentera Prepare for a Dramatic Weather Change

The orange alert is a reminder that summer conditions can change rapidly in the Balearic Islands during September.

Just days after temperatures reached around 36°C, Ibiza and Formentera are now preparing for torrential downpours, thunderstorms, hail, strong winds and waves of several metres.

The priority for Wednesday is safety.

Residents and visitors are being urged to avoid unnecessary risks, keep away from flood-prone and exposed coastal areas, secure loose objects and stay informed through official channels.

In an emergency, authorities remind the public to call 112.

Key Facts

• Main weather day: Wednesday, September 9, 2026

• Islands: Ibiza and Formentera

• Warning level: Orange

• Orange alert: 10:00 to 21:00

• Rainfall: Up to 40 litres per square metre in one hour

• Rainfall probability: 40% to 70%

• Thunderstorms: Expected

• Hail: Possible

• Storm wind gusts: Potentially above 90 km/h

• Coastal warning: Yellow from 08:00 to 23:59 Wednesday

• Coastal wind: North and northeast, around 40 to 60 km/h

• Waves: Around 2 to 4 metres

• Thursday: Yellow warnings during the early morning, with gradual improvement

• Expected temperature change: Around 10°C lower than earlier in the week

• Emergency number: 112