A data story about the practical maths of urban heat: where risk concentrates, which retrofits work together, and how a city can buy more survivable afternoons without pretending every street starts from the same place.
6chapters
5live charts
0external assets
Chapter 1
The afternoon baseline
By 3 pm, the official air temperature tells only part of the story. Asphalt, thin shade, glassy stops, and long waits add up to a felt-heat penalty. In this model corridor, the average trip feels 6.4°C hotter than the weather report.
The important part is not the headline temperature. It is the number of hours people spend above the local caution threshold.
42%of stops lack shade
19kdaily exposed trips
Felt heat builds faster than air temperature
Hourly model for a midsummer corridor
The danger window is not a spike. It is a long plateau.
Chapter 2
Heat does not land evenly
The same forecast produces different street conditions. Older residents, renters, and outdoor workers are more exposed where canopy cover is lower and bus stops are bare.
The first budget question is therefore geographical: which blocks carry the largest combined heat burden?
Neighbourhood heat-burden index
Higher combines exposure, low shade, and vulnerable population share
Two districts create nearly half the citywide exposure hours.
Chapter 3
The intervention stack
No single retrofit carries the programme. Shade lowers peak exposure, cool roofs reduce stored heat, shelters protect waiting time, and water stops reduce health risk during the final kilometre.
As this chapter enters view, the strongest layer for the current scroll position lights up.
Chapter 4
A day in the corridor
The retrofit does not make the day cold. It compresses the peak and shortens the unsafe period. That difference matters for workers who cannot choose a cooler hour and for passengers whose wait is fixed by the timetable.
Drag or tap the chart to inspect an hour.
Hourly heat index, before and after upgrades
Tap the chart for an hour-by-hour annotation
At 15:00 the upgraded corridor is 4.8°C cooler.
Chapter 5
Where the budget bends the curve
The cheapest item is not always the best first item. A useful programme asks how much exposure disappears for each million dollars, then checks whether the money reaches the people with the highest burden.
Focus or hover a bubble to read the trade-off.
Cost versus exposure reduction
Bubble size indicates equity reach
Chapter 6
What changes by 2030
The dividend is measured in fewer dangerous hours, shorter exposed waits, and a smaller gap between the coolest and hottest districts. Move the ambition control to see the programme scale.
The point is not that infrastructure solves heat alone. It is that street-level choices change who can safely move through the city.