The summer Europe ran hot

Barrelheads loads daily weather for its mapped wine regions from ERA5-Land, the Copernicus reanalysis, with records back to 1950. This issue covers the twenty-nine northern-hemisphere regions with weather tracking enabled, measured over the common window 1 April to 21 September 2026 — the latest date for which all twenty-nine are loaded. Warmth is summed as growing degree days above 10 °C, the standard viticultural measure of heat accumulated while vines are active, computed exactly as on our season page from each day's maximum and minimum; rain is the total over the same window; and each region's 2026 is set against its own 1991–2020 average, then ranked among the seventy-seven years since 1950 with the full window on file.

The headline is blunt. In twenty-one of the twenty-nine regions, 2026 is the warmest April-to-September window in the record. The median region ran 38.7 per cent above its 1991–2020 degree-day average and received 38 per cent less rain than normal. No year in the series — not 2003, not 2018, not 2022 — covers as much of the map at once.

The sharpest departures were not in the hot south but at the cool margins. Chablis accumulated 1,676 degree days against a norm of 1,108, a departure of 51 per cent, on 156 mm of rain where 376 mm is usual. Kent and Sussex, the coolest region we track, ran 49.4 per cent above normal — yet recorded not a single day at or above 35 °C, heat without extremes. The Mosel finished 42.7 per cent up, with five days at or above 35 °C against a long-run average of one such day a decade. Champagne ran 43.1 per cent above its norm on half its usual rain: 186 mm against 370 mm.

The classic heartlands were warm in absolute rather than relative terms. Pauillac logged 2,069 degree days against a norm of 1,478 — the warmest of its seventy-seven seasons — and Saint-Émilion counted nineteen days at or above 35 °C where its average is three. Tuscany counted thirty-one such days against an average of two and a half. Piedmont ran 38.7 per cent above normal on exactly half its usual rain, 218 mm against 436 mm. Spain carried the single largest departure: Rioja finished 55.5 per cent above its degree-day norm, with seventeen days at or above 35 °C where one is typical, and Ribera del Duero ran 43.6 per cent up on 118 mm of rain.

The nearest prior seasons, by heat alone — the season boards match on rain and hot days as well, which can pick a different year — were 2018 in the north: Chablis, Champagne, the Mosel; and 2022 in the west and south: Pauillac, Piedmont, Rioja. The gaps are what stand out. Pauillac's closest year, 2022, sits 218 degree days below 2026; Rioja's, also 2022, sits 164 below; Chablis's, 2018, sits 222 below. Only the Mosel came close to being matched, with 2018 just 26 degree days short, and Champagne's 2018 was 74 short. In most of Europe, 2026 did not edge past earlier warm seasons; it cleared them by a wide margin.

The exceptions mark the heat as European rather than hemispheric. Napa finished 2.1 per cent above its norm, twenty-third of seventy-seven; the Willamette Valley 8.9 per cent up; the Finger Lakes 7.2 per cent up and 19 per cent wetter than normal. Santorini sat 3.3 per cent above its average. Within Europe, only the Rheingau (second), Jerez (third), Madeira (fourth) and Tokaj (sixth) missed first place — each still a top-six season. Tokaj's distinction was dryness rather than heat: 137 mm of rain against a 394 mm norm, a shortfall of 65 per cent.

Two cautions belong with the numbers. ERA5-Land is a model-gridded reanalysis, not a network of vineyard weather stations; individual slopes, frost pockets and coastal strips will have run warmer or cooler than their grid cell. And the window closes on 21 September, so anything the back end of the season brings is not counted here. Degree days measure warmth, not wine. This issue records what the season measured, and makes no claim about what 2026 will be like in the glass.

The running season boards, updated weekly, remain at /intelligence/season.