London Heathrow · 1960–2026
How many days each year cleared 25 °C and 30 °C, and how many nights stayed at or above 15 °C and 20 °C — from the actual airport thermometer. The dashed line marks each metric's 1961–1990 climate normal; nearly every recent year now sits well above it.
Source: ECA&D official daily series (to 31 May 2026), topped up with Heathrow METAR observations to 8 Jul 2026. 2026 is a part-year (hatched).
All-time rankings
The ten highest years for each measure. Use the toggle above to rank on full-year totals or the same Jan 1–8 Jul window (which judges the part-year 2026 fairly). 2026 (✷) is highlighted wherever it lands, with its rank even outside the top ten.
Longest streaks
The longest run of consecutive days or nights meeting each threshold, ranked across every year. Respects the toggle — full-year or the same Jan 1–8 Jul window. 2026 (✷) is highlighted wherever it lands.
Within the year
Every qualifying day since 1960, folded onto one calendar. Hot days spread across a broad summer, but ≥30 °C days and tropical nights compress into a narrow mid-July-to-August window — they need a run of settled heat, not just a warm spell.