More than air temperature
Comfort outdoors is the combination of what the air is doing, how much radiation reaches a body from the sun and the surfaces around it, and how much of that a person can shed to the wind. Two spots a few metres apart, one under a canopy in a breeze and one against a sunlit wall in still air, can feel like different seasons. Air temperature alone, the number a thermometer gives, explains a fraction of the difference.
UTCI, one number for the combination
The index we map is UTCI, the universal thermal climate index. It converts air temperature, radiation, humidity and wind into the temperature that would produce the same physiological response in a reference environment, and sorts the result into bands from no thermal stress to extreme heat stress. Computed from a simulation, it exists at every point of a square for every hour of a typical year, not just where a weather station happens to stand.
Designing for the seasons
A good public space works in more than one season, and the requirements pull in opposite directions: summer wants shade and moving air, spring and autumn want sun and shelter, winter wants both sun and wind protection. Seasonal comfort maps show how a design balances these demands, and what a pergola, a tree row or a windbreak changes before anything is planted or built. For an investor in terraces, playgrounds or event spaces, the maps translate directly into usable hours per year.
Where this shows up in our work