Solar surge hits most of Europe in August

Most of Europe enjoyed a strong month for PV production in August, with high-pressure weather patterns delivering dry, settled conditions and consistently above-average irradiance levels. The one exception was adjacent to the Mediterranean, where increased storm activity and the remnants of Hurricane Erin tempered solar output. August 2025 marked one of the most productive months for European PV this decade, particularly across the western half of the continent

High-pressure patterns were dominant across Western Europe throughout the month, with the Azores High over the north Atlantic being stronger than usual and extending its influence over the continent. This suppressed cloud formation and enabled consistent sunshine. Solcast data shows that irradiance across much of the region was 10-15% above the August norm, driving a notable boost in estimated PV production. The east of Scotland and the southern provinces of Sweden reached 20% above normal, although at those high latitudes this only amounted to around 4.5kWh/m2 per day.

Belgium saw output rise 14% above the long-term average for August, per unit of installed capacity, while the Netherlands and Germany registered 11% and 8% gains, respectively. Great Britain also recorded a strong performance, with estimated production 7% above its usual August levels. France was closer to average, at 3% above normal.

For many countries in Europe, this year’s conditions made it the second-strongest August for PV output per unit of installed capacity for any August since 2014, behind only 2022. With installed solar capacity continuing to expand, this month’s total production still reached a new record high. The settled weather was linked to the persistence of high-pressure systems, which kept Atlantic storm systems at bay and reduced cloud cover across central and northern Europe.

In contrast, solar conditions were less favourable across the Mediterranean basin. Portugal, Spain, Italy, and Greece experienced irradiance levels close to or slightly below their long-term averages for August. Solcast estimates that Italy's PV production was 1% below the historical norm, with similarly muted performance across much of the Iberian Peninsula. The region was repeatedly impacted by low-pressure systems and summer thunderstorm outbreaks, which suppressed irradiance and introduced greater day-to-day variability.

Some of the thunderstorm events in parts of Spain and Italy brought giant hailstones, posing a direct threat to PV infrastructure. The end of the month saw the remnants of Hurricane Erin, after crossing the Atlantic, deliver a burst of severe weather across northern Italy and the surrounding Mediterranean. Associated cloud cover and rainfall further suppressed irradiance, capping production potential in the final days of the month.

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