Ibiza's water reserves fell sharply during August, dropping from 42% in July to 37% at the end of the month as the island experienced a particularly hot and dry period.

The figures, published by the Balearic Government on September 5, show that Ibiza recorded the largest monthly decline in water reserves of any island in the Balearic archipelago.

Despite the five-point fall, Ibiza's water-demand unit remains in a pre-alert drought situation rather than moving into the more serious alert category.

The deterioration came during an exceptionally warm August across the Balearic Islands. According to Aemet, August 2026 was the hottest August recorded in the islands since comparable records began in 1961, with an average temperature of 28.3°C, 2.7°C above the normal climatic average.

Ibiza's reserves fall five percentage points

At the end of July, Ibiza's water reserves stood at 42%.

By the end of August, that figure had fallen to 37%.

The five-point decline was the largest recorded among the Balearic Islands during the month. Mallorca declined from 39% to 38%, while Menorca fell from 34% to 33%.

Across the Balearics as a whole, water reserves fell from 39% in July to 38% in August. They were also two percentage points lower than in August 2025, when the archipelago's reserves stood at 40%.

For Ibiza, the latest result continues the downward trend seen during the summer.

The island had already fallen from 47% to 42% during July, meaning reserves have now declined by a total of 10 percentage points since June.

Ibiza remains in pre-alert

Despite the reduction, Ibiza has not entered the alert phase.

The Balearic Government classifies Ibiza's water-demand unit as being in a pre-alert situation. The same category currently applies to Menorca, Palma-Alcúdia, Tramuntana Nord and Tramuntana Sud.

Several other areas of the archipelago are in a more serious alert situation.

Artà moved into alert during August, while Es Pla, Manacor-Felanitx and Migjorn also remain in alert.

Formentera is currently the only water-demand unit in the Balearic Islands that remains in a state of normality.

The government data show that, by territory, 1.6% of the Balearic Islands is currently in normality, 60.8% is in pre-alert and 37.6% is in alert.

August was exceptionally dry in Ibiza

The decline in reserves coincided with very limited rainfall.

Aemet recorded only 7.1 litres of rain per square metre in Ibiza during August.

The normal climatic average for the island during the month is 23.7 litres per square metre.

That represents a substantial rainfall deficit and helps explain why the island's water reserves continued to decline during the summer.

Formentera recorded 10 litres per square metre against a normal average of 13.4 litres, while Mallorca recorded 8.8 litres compared with 21.1 and Menorca received 6.1 litres compared with a normal 16.2 litres.

Across the Balearic Islands, only 9.6 litres per square metre were recorded during August, compared with a climatic average of 21.4 litres.

The resulting precipitation deficit for the archipelago was 55%.

The hottest August since 1961

The lack of rain came alongside exceptional heat.

Aemet recorded an average temperature of 28.3°C across the Balearic Islands during August, which was 2.7°C above the normal average.

The agency classified the month as extremely warm and confirmed that it was the hottest August recorded in the Balearics since 1961.

Several areas of the islands recorded temperatures approaching or exceeding 40°C.

In Ibiza, Sant Joan de Labritja recorded a maximum of 39.2°C during the month. Formentera reached 35.3°C, while Cala Galdana in Menorca recorded 37.9°C.

The combination of very high temperatures and below-average rainfall increased pressure on water resources during one of the busiest periods of the year.

Water demand rises during the summer

Ibiza's falling reserves come during a period when demand for water is naturally higher.

The island's population increases significantly during the tourism season, placing additional pressure on drinking-water supplies, groundwater resources and other infrastructure.

The Balearic Government's July figures had already linked the seasonal decline in reserves to the increase in demand during summer. Ibiza fell by five percentage points that month alone, from 47% to 42%.

The further five-point reduction in August shows that the pressure continued into the second half of the summer.

Ibiza's reserves are below last year's August level

The latest figures also show that the situation is worse than it was at the same point last year.

The Balearic Islands as a whole ended August 2026 with reserves at 38%, compared with 40% in August 2025.

The government figures provided for Ibiza's August result show that the island fell to 37%, although the published comparison focuses on the month-to-month decline and the overall Balearic position.

This makes the latest result part of a broader deterioration across the archipelago, rather than an isolated change affecting Ibiza alone.

The Pityusic Islands still have an important water buffer

Despite the difficult August, there is one positive element in the wider data for Ibiza and Formentera.

The accumulated rainfall over the previous 12 months in the Pityusic Islands is currently at 120% of the climatic average.

That is the highest interannual rainfall figure among the Balearic Islands.

Menorca stands at 102% and Mallorca at 95%. Across the entire Balearic archipelago, accumulated rainfall over the same period is at 99% of the climatic average.

This means that the current water situation cannot simply be described as the result of an entire year without rain.

Instead, the latest deterioration reflects the particularly dry and hot conditions experienced during August, combined with the seasonal pressure on water resources.

Why the five-point fall matters

A five-percentage-point decline in a single month is significant because it represents a rapid deterioration during the period when the island experiences its greatest seasonal demand.

Ibiza entered August with reserves at 42% and finished the month at 37%.

That follows the five-point decline already recorded in July.

In just two months, reserves have therefore fallen from 47% in June to 37% at the end of August.

Although the island remains in pre-alert rather than alert, the direction of travel is closely watched because further deterioration could change the drought classification.

Ibiza is not the only island facing worsening conditions

The deterioration was widespread throughout the Balearics.

Mallorca's reserves fell from 39% to 38%, while Menorca's decreased from 34% to 33%.

The drought index also worsened across all 10 water-demand units during August.

Two areas changed drought categories as a result. Artà entered the alert phase and Tramuntana Sud moved from normality into pre-alert.

Only Formentera remained in normality.

The regional picture therefore shows a general deterioration, although Ibiza experienced the largest percentage-point fall in reserves during the month.

The drought index remains closely monitored

The Balearic Government also publishes a broader indicator for the Hydrological Demarcation.

The global index stood at 0.342 at the end of August.

That is higher than the 0.330 recorded a year earlier, but below the 0.364 registered in August 2024.

The indicator is used to monitor the evolution of available water resources and the drought situation across the different demand units.

The figures therefore provide a broader context for Ibiza's 37% reserve level.

Formentera remains the exception

Formentera currently stands apart from the rest of the archipelago.

Its water-demand unit remains in a state of normality despite the dry August.

The island received 10 litres of rain per square metre during the month, compared with a climatic average of 13.4 litres.

While that was still below normal, the decline in reserves and drought conditions has not pushed Formentera out of the normality category.

The contrast between Formentera and Ibiza is particularly notable because the two islands form part of the same Pityusic island group and share many of the same broader climatic conditions.

A summer of extreme heat across the islands

The water figures form part of a wider pattern of extreme summer weather.

Aemet has also described the entire summer of 2026 as exceptionally hot. According to provisional figures reported by EFE, the meteorological summer from June 1 to August 31 was the hottest summer in the Spanish record, with an average temperature of 24.5°C, 2.5°C above the 1991-2020 reference average.

The particularly hot August in the Balearics was therefore part of an unusually warm wider summer rather than an isolated monthly event.

For Ibiza, the combination of heat and low rainfall has direct implications for water demand and the island's reserves.

What happens next for Ibiza's water reserves?

The September figures will be particularly important because they will show whether the deterioration continues after the peak of August.

September normally brings a gradual reduction in tourist pressure compared with the height of summer, although Ibiza remains a busy destination and significant demand for water continues.

Future rainfall will also play an important role.

The current data show that the Pityusic Islands have received 120% of their climatic-average rainfall over the preceding 12 months, meaning the longer-term picture is more favourable than the latest summer figures alone might suggest.

However, the immediate trend remains downward.

Ibiza's reserves have now fallen by 10 percentage points since June, reaching 37% at the end of August.

Ibiza's water situation in numbers

Water reserves in Ibiza, June 2026: 47%

Water reserves in Ibiza, July 2026: 42%

Water reserves in Ibiza, August 2026: 37%

August decline: 5 percentage points

Current drought classification: Pre-alert

August rainfall in Ibiza: 7.1 litres per square metre

Normal August rainfall: 23.7 litres per square metre

Balearic Islands August average temperature: 28.3°C

Temperature anomaly: +2.7°C

Balearic Islands rainfall deficit in August: 55%

Pityusic Islands accumulated rainfall over the previous 12 months: 120% of climatic average

Formentera drought classification: Normality

Ibiza faces a more challenging autumn after record heat

Ibiza has ended August with its water reserves at 37%, five points lower than the previous month and the steepest decline recorded among the Balearic Islands.

The fall followed an exceptionally dry August in which the island received less than one-third of its normal rainfall, while the Balearic Islands experienced their hottest August since 1961.

For now, Ibiza remains in the pre-alert drought category rather than alert, and the longer-term rainfall figure for the Pityusic Islands remains relatively strong at 120% of the climatic average.

The coming months will determine whether the island can stabilise its water reserves or whether the downward trend seen during July and August continues.

For an island preparing to move beyond the peak of the tourism season, rainfall and the evolution of water demand will now be closely watched.