Mapping the world’s cities where you can live comfortably without heating or air conditioning reveals how few boast such ideal climates – and how global warming may further narrow the field

Last summer I mapped the cities of the world where the residents can live comfortably without heating or air conditioning.

Working with Guardian Cities to scale up the original survey using data from the US National Oceanic and Atmospheric Administration, we broke the world’s cities into four categories.

First, cities where you probably don't need either heating or air conditioning: average summer temperatures are shy of 26.5C (80F) and the hottest hours of an average summer day are less than 28C (82F), while the winter average is no colder than 13C (55F) and the coldest days no less than 7C (45F). Second, cities that are warmer in the summer, meaning you probably want air conditioning but can still get by without heating. Third, the opposite: cold in winter, not too warm in summer. Lastly, cities with hot summers and cold winters, where you probably want both air conditioning and heating.

The good news is that, if you want to go air conditioning-free, you have options on every single continent. The bad news is that this may not be the case forever.

Using data from the Climate Impact Lab, we have modelled how climate change might affect temperatures globally, making more people dependent on air conditioning in cities where it is currently strictly a luxury.