Air temperature is what phones show. Vines also live at the soil skin.
WineGuide101’s August 2026 France harvest guide reports Bordeaux talk of ground temperatures near 50°C and leaf damage severe enough that some exposed parcels face yield cuts beyond 20%. Radiated heat from bare earth cooks canopies from below, stressing leaves that should shade fruit. When leaves scorch, photosynthesis drops and berries can stall or raisin.
Mini-concept: surface heat is a second climate. Mulch, cover crops and canopy density change how much of the sun’s energy bounces into the leaf layer. Two neighbouring rows can live different summers if one sits on bare, dark soil.
A Bordeaux bottle from a scorched parcel year is a physiology story in your glass — choose it knowingly instead of a can that never felt radiant heat from gravel.
Ask producers how they cooled the interrow in 2026. The answer (grass, mulch, kaolin, denser shade) is the real vintage note behind any score.
Keep the pattern: ~50°C ground talk, leaf scorch, >20% cuts on exposed sites — heat arrives from the soil up.