The June 2026 heatwave established a new benchmark for early-summer heat in Germany, producing the highest temperatures observed since instrumental records began and culminating in a new provisional national temperature record of 41.8 °C. Here, we quantify the extremeness of this event using high-resolution gridded observations, long-term station records extending back nearly two centuries, and ERA5 reanalysis, and investigate the relative contributions of atmospheric circulation and background climate warming. Across the 1951–2026 gridded record, the event ranks first in peak daily maximum temperature, cumulative heatwave intensity, and the number of days with daily maximum temperature exceeding 30 °C. Daily maximum temperature anomalies reached 12–16 °C locally, while regional peak temperatures exceeded the 1971–2000 climatology by up to 4.9 standard deviations and long-term station records by up to 3.7 standard deviations. At the national scale, heatwave duration and frequency have increased significantly since 1951, providing the long-term climatic context in which this event occurred. Flow-analogue analysis shows that the heatwave was generated by a persistent omega-type blocking anticyclone, but that comparable circulation patterns from the recent past would have produced 3–4 °C lower temperatures than those observed in 2026, indicating substantial thermodynamic amplification associated with background warming. Our results show that the June 2026 event represents a new class of intensity-dominated, record-shattering early-summer heatwaves in Germany, in which persistent atmospheric blocking acts upon a substantially warmer climate to produce unprecedented temperatures.