Urban heat › Cardiff
Urban heat island in Cardiff
On a clear summer afternoon, land-surface temperatures across Cardiff span roughly 18.8–38.1°C — the typical block near 30.7°C. The hottest streets run about 7.4°C above the city average; the coolest, around parks and water, about 11.9°C below. Measured from Landsat satellite thermal data.
Which parts of Cardiff are hottest in summer?
From Landsat satellite land-surface temperature, the hottest blocks in Cardiff run about 7.4°C above the city average on clear summer afternoons — typically dense city-centre, commercial and industrial land with lots of dark roofs, roads and hard standing. The coolest, about 11.9°C below average, are parks, water and leafy, well-vegetated suburbs. We measure this on a ~150 m grid (3,771 cells across Cardiff) and show any postcode's position as a percentile of the city.
Is this air temperature or how hot it feels in Cardiff?
No — it is land-SURFACE (skin) temperature: how hot the ground, roads and roofs get in the daytime sun (the satellite passes around 10:50am), not the air temperature you feel or your indoor/overnight temperature. It is a relative indicator of which parts of Cardiff are heat-exposed by their built environment, not a heat-health measurement.
How do I check a specific Cardiff postcode?
The £19 Novarly Parcel UK property report includes the urban-heat reading for the exact postcode — how many degrees hotter or cooler it runs than the Cardiff average, and its percentile — alongside flood, ground stability, radon, air quality, noise, crime, planning, schools, broadband, energy and sales history. Check any GB postcode free first.
Source: Landsat 8/9 Collection 2 Level-2 land-surface temperature (USGS/NASA, public domain) via the Microsoft Planetary Computer; several cloud-free summer scenes composited to a ~150 m grid. A relative daytime surface-heat indicator — not air temperature, overnight heat, or a heat-health assessment.
Novarly Parcel · official public data, read properly · parcel.novarly.com