Following on from a previous blog by our colleague Anastasiia Khil, we’ve taken a deeper dive into Land Surface Temperatures (LST) in London and Dublin, comparing two summer periods – 2014 and 2025.
Taking this deep dive into LSTs is Mallon Colleague Dara McGovern, who has created the following maps that provide a closer look at how heat can affect different areas of the cities.
A Deeper Dive into Urban Heat
Using the Landsat 8 satellite, we worked with a higher resolution sensor (30m² pixels) captured in the Thermal Energy Band (wavelengths between 10.5 and 12.5 micrometres) to model LST. This thermal energy represents the Earth’s emitted radiation, which we can convert into accurate surface temperature readings.
Our analysis was carried out in Google Earth Engine, enabling us to visualise temperature variations across both cities and identify areas most affected by the Urban Heat Island (UHI) effect.
Key Findings
|
Location |
2014 Mean (°C) |
2025 Mean (°C) |
|
London |
26.0 |
31.9 |
|
Dublin |
21.6 |
26.7 |
Notable Sites – London
- Wimbledon & Putney Commons: 18.8°C (2014) vs 25.1°C (2025)
- Croydon Industrial Estate: 35.6°C vs 39.2°C
- Loxford, Ilford (dense urban): 33.7°C vs 39.8°C
- Canary Wharf 31.2°C vs 35.7°C
- Greenwich: 40.9°C vs 35.8°C (a rare decrease)
Notable Sites – Dublin
- Phoenix Park: 17.6°C (2014) vs 22.2°C (2025)
- Blanchardstown Shopping Centre: 34.0°C vs 40.7°C
- Ballymount Industrial Estate (Red Cow area): 35.0°C vs 40.3°C
- Dublin Airport: 27.3°C vs 35.4°C
- Kilmashogue Mountain: 20.3°C vs 26.3°C
What the Data Tells Us
Areas with dense urban development and minimal vegetation or water bodies consistently record higher surface temperatures. The increase over 11 years is particularly striking in Dublin’s rapidly developing zones, such as Blanchardstown and the Red Cow Roundabout, where population growth and infrastructure expansion have intensified the UHI effect.
London’s overall increase is less pronounced, possibly because the city was already built up in 2014. However, the contrast between green spaces like Wimbledon and Putney Commons and surrounding urban areas underscores the cooling effect of vegetation.
Materials such as tarmac, concrete, and metal roofing trap and re–radiate heat, raising local temperatures. Conversely, parks and wooded areas help regulate urban temperatures, reducing peak LST by several degrees.
Why This Matters?
This analysis demonstrates the power of Remote Sensing and Earth Observation for tracking the thermal evolution of cities. By leveraging the spatial detail of Landsat imagery, urban planners and policy makers can:
- Pinpoint urban hotspots
- Prioritise cooling interventions such as increased green spaces, reflective building materials, or climate–conscious urban design
- Track the effectiveness of heat mitigation strategies over time
As Dublin continues to expand and London adapts to climate challenges, satellite–based evidence can guide data–driven urban development, helping create cooler, more sustainable, and climate–resilient cities.
